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Wetting is the ability of a liquid to maintain contact with a solid surface, resulting from intermolecular interactions when the two are brought together. This happens in presence of a gaseous phase or another liquid phase not miscible with the first one. The degree of wetting (wettability) is determined by a force balance between adhesive and cohesive forces | https://huggingface.co/datasets/fmars/wiki_stem |
Adhesion is the tendency of dissimilar particles or surfaces to cling to one another (cohesion refers to the tendency of similar or identical particles/surfaces to cling to one another).
The forces that cause adhesion and cohesion can be divided into several types. The intermolecular forces responsible for the function of various kinds of stickers and sticky tape fall into the categories of chemical adhesion, dispersive adhesion, and diffusive adhesion | https://huggingface.co/datasets/fmars/wiki_stem |
Atomic force microscopy (AFM) or scanning force microscopy (SFM) is a very-high-resolution type of scanning probe microscopy (SPM), with demonstrated resolution on the order of fractions of a nanometer, more than 1000 times better than the optical diffraction limit.
Overview
Atomic force microscopy (AFM) is a type of scanning probe microscopy (SPM), with demonstrated resolution on the order of fractions of a nanometer, more than 1000 times better than the optical diffraction limit. The information is gathered by "feeling" or "touching" the surface with a mechanical probe | https://huggingface.co/datasets/fmars/wiki_stem |
Bimodal Atomic Force Microscopy (bimodal AFM) is an advanced atomic force microscopy technique characterized by generating high-spatial resolution maps of material properties. Topography, deformation, elastic modulus, viscosity coefficient or magnetic field maps might be generated. Bimodal AFM is based on the simultaneous excitation and detection of two eigenmodes (resonances) of a force microscope microcantilever | https://huggingface.co/datasets/fmars/wiki_stem |
In chemistry and physics, cohesion (from Latin cohaesiō 'cohesion, unity'), also called cohesive attraction or cohesive force, is the action or property of like molecules sticking together, being mutually attractive. It is an intrinsic property of a substance that is caused by the shape and structure of its molecules, which makes the distribution of surrounding electrons irregular when molecules get close to one another, creating electrical attraction that can maintain a microscopic structure such as a water drop. Cohesion allows for surface tension, creating a "solid-like" state upon which light-weight or low-density materials can be placed | https://huggingface.co/datasets/fmars/wiki_stem |
Compliance constants are the elements of an inverted Hessian matrix. The calculation of compliance constants provides an alternative description of chemical bonds in comparison with the widely used force constants explicitly ruling out the dependency on the coordinate system. They provide the unique description of the mechanical strength for covalent and non-covalent bonding | https://huggingface.co/datasets/fmars/wiki_stem |
Dispersive adhesion, also called adsorptive adhesion, is a mechanism for adhesion which attributes attractive forces between two materials to intermolecular interactions between molecules of each material. This mechanism is widely viewed as the most important of the five mechanisms of adhesion due to its presence in every type of adhesive system and its relative strength.
Source of dispersive adhesion attractions
The source of adhesive forces, according to the dispersive adhesion mechanism, is the weak interactions that occur between molecules close together | https://huggingface.co/datasets/fmars/wiki_stem |
In molecular physics, the Hamaker constant (denoted A; named for H. C. Hamaker) is a physical constant that can be defined for a van der Waals (vdW) body–body interaction:
A
=
π
2
C
ρ
1
ρ
2
,
{\displaystyle A=\pi ^{2}C\rho _{1}\rho _{2},}
where ρ1, ρ2 are the number densities of the two interacting kinds of particles, and C is the London coefficient in the particle–particle pair interaction | https://huggingface.co/datasets/fmars/wiki_stem |
After the explanation of van der Waals forces by Fritz London, several scientists soon realised that his definition could be extended from the interaction of two molecules with induced dipoles to macro-scale objects by summing all of the forces between the molecules in each of the bodies involved. The theory is named after H. C | https://huggingface.co/datasets/fmars/wiki_stem |
In quantum mechanics, the Hellmann–Feynman theorem relates the derivative of the total energy with respect to a parameter to the expectation value of the derivative of the Hamiltonian with respect to that same parameter. According to the theorem, once the spatial distribution of the electrons has been determined by solving the Schrödinger equation, all the forces in the system can be calculated using classical electrostatics.
The theorem has been proven independently by many authors, including Paul Güttinger (1932), Wolfgang Pauli (1933), Hans Hellmann (1937) and Richard Feynman (1939) | https://huggingface.co/datasets/fmars/wiki_stem |
A hydrophile is a molecule or other molecular entity that is attracted to water molecules and tends to be dissolved by water. In contrast, hydrophobes are not attracted to water and may seem to be repelled by it. Hygroscopics are attracted to water, but are not dissolved by water | https://huggingface.co/datasets/fmars/wiki_stem |
In chemistry, hydrophobicity is the physical property of a molecule that is seemingly repelled from a mass of water (known as a hydrophobe). In contrast, hydrophiles are attracted to water.
Hydrophobic molecules tend to be nonpolar and, thus, prefer other neutral molecules and nonpolar solvents | https://huggingface.co/datasets/fmars/wiki_stem |
Organosilicon water repellent:
water solution of siliconate
The water-repelling liquid is applied:
To provide the surface of materials with excellent water resistance properties - the surface does not absorb water;
To make the material frost- and corrosion resistant;
To reduce the pollution of surface;In addition, the treated surface does not change its appearance, maintains air permeability - material is not sweated and retains the ability to output pairs.
The water-repelling liquid is applied:
To provide the surface of materials with excellent water resistance properties - the surface does not absorb water;
To make the material frost- and corrosion resistant;
To reduce the pollution of surface;In addition, the treated surface does not change its appearance, maintains air permeability - material is not sweated and retains the ability to output pairs.
The liquid is methyl hydride siloxane polymer with low viscosity of light-yellow color or colorless | https://huggingface.co/datasets/fmars/wiki_stem |
Hydrophobicity scales are values that define the relative hydrophobicity or hydrophilicity of amino acid residues. The more positive the value, the more hydrophobic are the amino acids located in that region of the protein. These scales are commonly used to predict the transmembrane alpha-helices of membrane proteins | https://huggingface.co/datasets/fmars/wiki_stem |
Membrane fusion is a key biophysical process that is essential for the functioning of life itself. It is defined as the event where two lipid bilayers approach each other and then merge to form a single continuous structure. In living beings, cells are made of an outer coat made of lipid bilayers; which then cause fusion to take place in events such as fertilization, embryogenesis and even infections by various types of bacteria and viruses | https://huggingface.co/datasets/fmars/wiki_stem |
Non-contact atomic force microscopy (nc-AFM), also known as dynamic force microscopy (DFM), is a mode of atomic force microscopy, which itself is a type of scanning probe microscopy. In nc-AFM a sharp probe is moved close (order of Angstroms) to the surface under study, the probe is then raster scanned across the surface, the image is then constructed from the force interactions during the scan. The probe is connected to a resonator, usually a silicon cantilever or a quartz crystal resonator | https://huggingface.co/datasets/fmars/wiki_stem |
Optical contact bonding is a glueless process whereby two closely conformal surfaces are joined together, being held purely by intermolecular forces.
History
Isaac Newton has been credited with the first description of conformal interaction observed through the interference phenomenon known as Newton's rings, though it was S. D | https://huggingface.co/datasets/fmars/wiki_stem |
Photoconductive atomic force microscopy (PC-AFM) is a variant of atomic force microscopy that measures photoconductivity in addition to surface forces.
Background
Multi-layer photovoltaic cells have gained popularity since mid 1980s. At the time, research was primarily focused on single-layer photovoltaic (PV) devices between two electrodes, in which PV properties rely heavily on the nature of the electrodes | https://huggingface.co/datasets/fmars/wiki_stem |
In chemistry, π-effects or π-interactions are a type of non-covalent interaction that involves π systems. Just like in an electrostatic interaction where a region of negative charge interacts with a positive charge, the electron-rich π system can interact with a metal (cationic or neutral), an anion, another molecule and even another π system. Non-covalent interactions involving π systems are pivotal to biological events such as protein-ligand recognition | https://huggingface.co/datasets/fmars/wiki_stem |
The Surface Force Apparatus (SFA) is a scientific instrument which measures the interaction force of two surfaces as they are brought together and retracted using multiple beam interferometry to monitor surface separation and directly measure contact area and observe any surface deformations occurring in the contact zone. One surface is held by a cantilevered spring, and the deflection of the spring is used to calculate the force being exerted. The technique was pioneered by David Tabor and R | https://huggingface.co/datasets/fmars/wiki_stem |
Surface tension is the tendency of liquid surfaces at rest to shrink into the minimum surface area possible. Surface tension is what allows objects with a higher density than water such as razor blades and insects (e. g | https://huggingface.co/datasets/fmars/wiki_stem |
In chemistry and materials science, ultrahydrophobic (or superhydrophobic) surfaces are highly hydrophobic, i. e. , extremely difficult to wet | https://huggingface.co/datasets/fmars/wiki_stem |
In molecular physics, the van der Waals force is a distance-dependent interaction between atoms or molecules. Unlike ionic or covalent bonds, these attractions do not result from a chemical electronic bond; they are comparatively weak and therefore more susceptible to disturbance. The van der Waals force quickly vanishes at longer distances between interacting molecules | https://huggingface.co/datasets/fmars/wiki_stem |
The van der Waals radius, rw, of an atom is the radius of an imaginary hard sphere representing the distance of closest approach for another atom.
It is named after Johannes Diderik van der Waals, winner of the 1910 Nobel Prize in Physics, as he was the first to recognise that atoms were not simply points and to demonstrate the physical consequences of their size through the van der Waals equation of state.
van der Waals volume
The van der Waals volume, Vw, also called the atomic volume or molecular volume, is the atomic property most directly related to the van der Waals radius | https://huggingface.co/datasets/fmars/wiki_stem |
Acta Materialia is a peer-reviewed scientific journal published twenty times per year on behalf of Acta Materialia Inc. The current publisher is Elsevier. The coordinating editor is Christopher A | https://huggingface.co/datasets/fmars/wiki_stem |
Advanced Energy Materials is a peer-reviewed scientific journal covering energy-related research, including photovoltaics, batteries, supercapacitors, fuel cells, hydrogen technologies, thermoelectrics, photocatalysis, solar power technologies, magnetic refrigeration, and piezoelectric materials. It publishes invited reviews and progress reports, full papers, and rapid communications. Established in 2011, Adv | https://huggingface.co/datasets/fmars/wiki_stem |
Advanced Functional Materials is a peer-reviewed scientific journal, published by Wiley-VCH. Established in February 2001, the journal began to publish monthly in 2002 and moved to 18/year in 2006, biweekly in 2008, and weekly in 2013.
It has been published under other titles since 1985 | https://huggingface.co/datasets/fmars/wiki_stem |
Advanced Materials is a weekly peer-reviewed scientific journal covering materials science. It includes communications, reviews, and feature articles on topics in chemistry, physics, nanotechnology, ceramics, metallurgy, and biomaterials. According to the Journal Citation Reports, the journal has a 2022 impact factor of 29 | https://huggingface.co/datasets/fmars/wiki_stem |
Advanced Optical Materials is a monthly peer-reviewed scientific journal published by Wiley-VCH. It was established in 2013, after a section with the same name had been published since March 2012 in Advanced Materials. It covers all aspects of light-matter interactions | https://huggingface.co/datasets/fmars/wiki_stem |
The Annual Review of Materials Research is a peer-reviewed journal that publishes review articles about materials science. It has been published by the nonprofit Annual Reviews since 1971, when it was first released under the title the Annual Review of Materials Science. Three people have served as editors, with the current editor David R | https://huggingface.co/datasets/fmars/wiki_stem |
Applied Physics A: Materials Science and Processing is a peer-reviewed scientific journal that is published monthly by Springer Science+Business Media. The editor-in-chief is Thomas Lippert (Paul Scherrer Institute). This publication is complemented by Applied Physics B (Lasers & Optics) | https://huggingface.co/datasets/fmars/wiki_stem |
Applied Spectroscopy is a peer-reviewed scientific journal published monthly by the Society for Applied Spectroscopy, and it is also the official journal for this society. The editor-in-chief is Sergei G. Kazarian (Imperial College London) | https://huggingface.co/datasets/fmars/wiki_stem |
Biomaterials is a peer-reviewed scientific journal covering research on and applications of biomaterials. It is published by Elsevier. The editor-in-chief is Kam W | https://huggingface.co/datasets/fmars/wiki_stem |
Carbon is a scientific journal published by Elsevier. According to the journal's website, "Carbon publishes papers that deal with original research on carbonaceous solids with an emphasis on graphene-based materials. These materials include, but are not limited to, carbon nanotubes, carbon fibers and filaments, graphites, activated carbons, pyrolytic carbons, glass-like carbons, carbon blacks, and chars | https://huggingface.co/datasets/fmars/wiki_stem |
Chemical Vapor Deposition was a monthly peer-reviewed scientific journal covering materials science. It was established in 1995 and ceased independent publication in 2015, when it became a section of Advanced Materials Interfaces. The journal was published by Wiley-VCH and the editor-in-chief was Peter Gregory | https://huggingface.co/datasets/fmars/wiki_stem |
Electron magnetic circular dichroism (EMCD) (also known as electron energy-loss magnetic chiral dichroism) is the EELS equivalent of XMCD.
The effect was first proposed in 2003 and experimentally confirmed in 2006 by the group of Prof. Peter Schattschneider at the Vienna University of Technology | https://huggingface.co/datasets/fmars/wiki_stem |
Electron phenomenological spectroscopy (EPS) is based on the correlations between integral optical characteristics and properties of substance as a single whole quantum continuum: spectrum-properties and color-properties. According to these laws the physicochemical properties of substance solutions in ultraviolet (UV), visible light and near infrared (IR) regions of the electromagnetic spectrum are in proportion to the quantity of radiation absorbed. Such aspects of electron spectroscopy have been shown in the works of Mikhail Yu Dolomatov and has been named electron phenomenological spectroscopy because the integral characteristics of the system are studied | https://huggingface.co/datasets/fmars/wiki_stem |
Electron spectroscopy refers to a group formed by techniques based on the analysis of the energies of emitted electrons such as photoelectrons and Auger electrons. This group includes X-ray photoelectron spectroscopy (XPS), which also known as Electron Spectroscopy for Chemical Analysis (ESCA), Electron energy loss spectroscopy (EELS), Ultraviolet photoelectron spectroscopy (UPS), and Auger electron spectroscopy (AES). These analytical techniques are used to identify and determine the elements and their electronic structures from the surface of a test sample | https://huggingface.co/datasets/fmars/wiki_stem |
Electroreflectance (also: electromodulated reflectance) is the change of reflectivity of a solid due to the influence of an electric field close to, or at the interface of the solid with a liquid. The change in reflectivity is most noticeable at very specific ranges of photon energy, corresponding to the band gaps at critical points of the Brillouin zone. The electroreflectance effect can be used to get a clearer picture of the band structure at critical points where there is a lot of near degeneracy | https://huggingface.co/datasets/fmars/wiki_stem |
An electrostatic lens is a device that assists in the transport of charged particles. For instance, it can guide electrons emitted from a sample to an electron analyzer, analogous to the way an optical lens assists in the transport of light in an optical instrument. Systems of electrostatic lenses can be designed in the same way as optical lenses, so electrostatic lenses easily magnify or converge the electron trajectories | https://huggingface.co/datasets/fmars/wiki_stem |
Ellipsometry is an optical technique for investigating the dielectric properties (complex refractive index or dielectric function) of thin films. Ellipsometry measures the change of polarization upon reflection or transmission and compares it to a model.
It can be used to characterize composition, roughness, thickness (depth), crystalline nature, doping concentration, electrical conductivity and other material properties | https://huggingface.co/datasets/fmars/wiki_stem |
A quantum mechanical system or particle that is bound—that is, confined spatially—can only take on certain discrete values of energy, called energy levels. This contrasts with classical particles, which can have any amount of energy. The term is commonly used for the energy levels of the electrons in atoms, ions, or molecules, which are bound by the electric field of the nucleus, but can also refer to energy levels of nuclei or vibrational or rotational energy levels in molecules | https://huggingface.co/datasets/fmars/wiki_stem |
The Federation of Analytical Chemistry and Spectroscopy Societies or FACSS is a scientific society incorporated on June 28, 1972, with the goal of promoting research and education in analytical chemistry. The organization combined the many smaller meetings of the individual societies into an annual meeting that includes all of analytical chemistry. The meetings are intended to provide a forum for scientists to address the development of analytical chemistry, chromatography, and spectroscopy | https://huggingface.co/datasets/fmars/wiki_stem |
Ferromagnetic resonance, or FMR, is coupling between an electromagnetic wave and the magnetization of a medium through which it passes. This coupling induces a significant loss of power of the wave. The power is absorbed by the precessing magnetization (Larmor precession) of the material and lost as heat | https://huggingface.co/datasets/fmars/wiki_stem |
Flickering analysis of cellular or membranous structures is a widespread technique for measuring the bending modulus and other properties from the power spectrum of thermal fluctuations.
First demonstrated theoretically by Brochard and Lennon in 1975, flickering spectroscopy has become a widespread technique due to its simplicity and lack of specialised equipment beyond a brightfield microscope. It is used in structures such as red blood cells, giant unilamellar vesicles and other cell-like structures | https://huggingface.co/datasets/fmars/wiki_stem |
Fluorescence correlation spectroscopy (FCS) is a statistical analysis, via time correlation, of stationary fluctuations of the fluorescence intensity. Its theoretical underpinning originated from L. Onsager's regression hypothesis | https://huggingface.co/datasets/fmars/wiki_stem |
Fluorescence cross-correlation spectroscopy (FCCS) is a spectroscopic technique that examines the interactions of fluorescent particles of different colours as they randomly diffuse through a microscopic detection volume over time, under steady conditions.
Discovery
Eigen and Rigler first introduced the fluorescence cross-correlation spectroscopy (FCCS) method in 1994. Later, in 1997, Schwille experimentally implemented this method | https://huggingface.co/datasets/fmars/wiki_stem |
Fluorescence spectroscopy (also known as fluorimetry or spectrofluorometry) is a type of electromagnetic spectroscopy that analyzes fluorescence from a sample. It involves using a beam of light, usually ultraviolet light, that excites the electrons in molecules of certain compounds and causes them to emit light; typically, but not necessarily, visible light. A complementary technique is absorption spectroscopy | https://huggingface.co/datasets/fmars/wiki_stem |
In spectroscopy, a forbidden mechanism (forbidden transition or forbidden line) is a spectral line associated with absorption or emission of photons by atomic nuclei, atoms, or molecules which undergo a transition that is not allowed by a particular selection rule but is allowed if the approximation associated with that rule is not made. For example, in a situation where, according to usual approximations (such as the electric dipole approximation for the interaction with light), the process cannot happen, but at a higher level of approximation (e. g | https://huggingface.co/datasets/fmars/wiki_stem |
Force spectroscopy is a set of techniques for the study of the interactions and the binding forces between individual molecules. These methods can be used to measure the mechanical properties of single polymer molecules or proteins, or individual chemical bonds. The name "force spectroscopy", although widely used in the scientific community, is somewhat misleading, because there is no true matter-radiation interaction | https://huggingface.co/datasets/fmars/wiki_stem |
Fourier-transform spectroscopy is a measurement technique whereby spectra are collected based on measurements of the coherence of a radiative source, using time-domain or space-domain measurements of the radiation, electromagnetic or not. It can be applied to a variety of types of spectroscopy including optical spectroscopy, infrared spectroscopy (FTIR, FT-NIRS), nuclear magnetic resonance (NMR) and magnetic resonance spectroscopic imaging (MRSI), mass spectrometry and electron spin resonance spectroscopy.
There are several methods for measuring the temporal coherence of the light (see: field-autocorrelation), including the continuous-wave and the pulsed Fourier-transform spectrometer or Fourier-transform spectrograph | https://huggingface.co/datasets/fmars/wiki_stem |
The Franck–Condon principle (named for James Franck and Edward Condon) is a rule in spectroscopy and quantum chemistry that explains the intensity of vibronic transitions (the simultaneous changes in electronic and vibrational energy levels of a molecule due to the absorption or emission of a photon of the appropriate energy). The principle states that during an electronic transition, a change from one vibrational energy level to another will be more likely to happen if the two vibrational wave functions overlap more significantly.
Overview
The Franck–Condon principle has a well-established semiclassical interpretation based on the original contributions of James Franck | https://huggingface.co/datasets/fmars/wiki_stem |
In optics, a frequency comb is a laser source whose spectrum consists of a series of discrete, equally spaced frequency lines. Frequency combs can be generated by a number of mechanisms, including periodic modulation (in amplitude and/or phase) of a continuous-wave laser, four-wave mixing in nonlinear media, or stabilization of the pulse train generated by a mode-locked laser. Much work has been devoted to this last mechanism, which was developed around the turn of the 21st century and ultimately led to one half of the Nobel Prize in Physics being shared by John L | https://huggingface.co/datasets/fmars/wiki_stem |
Full spectral imaging (FSI) is a form of imaging spectroscopy and is the successor to hyperspectral imaging. Full spectral imaging was developed to improve the capabilities of remote sensing including Earth remote sensing.
Data acquisition
Whereas hyperspectral imaging acquires data as many contiguous spectral bands, full spectral imaging acquires data as spectral curves | https://huggingface.co/datasets/fmars/wiki_stem |
Functional magnetic resonance spectroscopy of the brain (fMRS) uses magnetic resonance imaging (MRI) to study brain metabolism during brain activation. The data generated by fMRS usually shows spectra of resonances, instead of a brain image, as with MRI. The area under peaks in the spectrum represents relative concentrations of metabolites | https://huggingface.co/datasets/fmars/wiki_stem |
The fundamental series is a set of spectral lines in a set caused by transition between d and f orbitals in atoms.
Originally the series was discovered in the infrared by Fowler and independently by Arno Bergmann. This resulted in the name Bergmann series used for such a set of lines in a spectrum | https://huggingface.co/datasets/fmars/wiki_stem |
Gamma-ray spectroscopy is the qualitative study of the energy spectra of gamma-ray sources, such as in the nuclear industry, geochemical investigation, and astrophysics. Gamma-ray spectrometry, on the other hand, is the method used to acquire a quantitative spectrum measurement. Most radioactive sources produce gamma rays, which are of various energies and intensities | https://huggingface.co/datasets/fmars/wiki_stem |
Gas chromatography–vacuum ultraviolet spectroscopy (GC-VUV) is a universal detection technique for gas chromatography. VUV detection provides both qualitative and quantitative spectral information for most gas phase compounds.
GC-VUV spectral data is three-dimensional (time, absorbance, wavelength) and specific to chemical structure | https://huggingface.co/datasets/fmars/wiki_stem |
Gas in scattering media absorption spectroscopy (GASMAS) is an optical technique for sensing and analysis of gas located within porous and highly scattering solids, e. g. powders, ceramics, wood, fruit, translucent packages, pharmaceutical tablets, foams, human paranasal sinuses etc | https://huggingface.co/datasets/fmars/wiki_stem |
The GF method, sometimes referred to as FG method, is a classical mechanical method introduced by Edgar Bright Wilson to obtain certain internal coordinates for a vibrating semi-rigid molecule, the so-called normal coordinates Qk. Normal coordinates decouple the classical vibrational motions of the molecule and thus give an easy route to obtaining vibrational amplitudes of the atoms as a function of time. In Wilson's GF method it is assumed that the molecular kinetic energy consists only of harmonic vibrations of the atoms, i | https://huggingface.co/datasets/fmars/wiki_stem |
A Grotrian diagram, or term diagram, shows the allowed electronic transitions between the energy levels of atoms. They can be used for one-electron and multi-electron atoms. They take into account the specific selection rules related to changes in angular momentum of the electron | https://huggingface.co/datasets/fmars/wiki_stem |
Modern spectroscopy in the Western world started in the 17th century. New designs in optics, specifically prisms, enabled systematic observations of the solar spectrum. Isaac Newton first applied the word spectrum to describe the rainbow of colors that combine to form white light | https://huggingface.co/datasets/fmars/wiki_stem |
HITRAN (an acronym for High Resolution Transmission) molecular spectroscopic database is a compilation of spectroscopic parameters used to simulate and analyze the transmission and emission of light in gaseous media, with an emphasis on planetary atmospheres. The knowledge of spectroscopic parameters for transitions between energy levels in molecules (and atoms) is essential for interpreting and modeling the interaction of radiation (light) within different media.
For half a century, HITRAN has been considered to be an international standard which provides the user a recommended value of parameters for millions of transitions for different molecules | https://huggingface.co/datasets/fmars/wiki_stem |
In rotational-vibrational and electronic spectroscopy of diatomic molecules, Hund's coupling cases are idealized descriptions of rotational states in which specific terms in the molecular Hamiltonian and involving couplings between angular momenta are assumed to dominate over all other terms. There are five cases, proposed by Friedrich Hund in 1926-27 and traditionally denoted by the letters (a) through (e). Most diatomic molecules are somewhere between the idealized cases (a) and (b) | https://huggingface.co/datasets/fmars/wiki_stem |
Hydrogen–deuterium exchange (also called H–D or H/D exchange) is a chemical reaction in which a covalently bonded hydrogen atom is replaced by a deuterium atom, or vice versa. It can be applied most easily to exchangeable protons and deuterons, where such a transformation occurs in the presence of a suitable deuterium source, without any catalyst. The use of acid, base or metal catalysts, coupled with conditions of increased temperature and pressure, can facilitate the exchange of non-exchangeable hydrogen atoms, so long as the substrate is robust to the conditions and reagents employed | https://huggingface.co/datasets/fmars/wiki_stem |
Hyperchromicity is the increase of absorbance (optical density) of a material. The most famous example is the hyperchromicity of DNA that occurs when the DNA duplex is denatured. The UV absorption is increased when the two single DNA strands are being separated, either by heat or by addition of denaturant or by increasing the pH level | https://huggingface.co/datasets/fmars/wiki_stem |
Hyperspectral imaging collects and processes information from across the electromagnetic spectrum. The goal of hyperspectral imaging is to obtain the spectrum for each pixel in the image of a scene, with the purpose of finding objects, identifying materials, or detecting processes. There are three general types of spectral imagers | https://huggingface.co/datasets/fmars/wiki_stem |
In imaging spectroscopy (also hyperspectral imaging or spectral imaging) each pixel of an image acquires many bands of light intensity data from the spectrum, instead of just the three bands of the RGB color model. More precisely, it is the simultaneous acquisition of spatially coregistered images in many spectrally contiguous bands.
Some spectral images contain only a few image planes of a spectral data cube, while others are better thought of as full spectra at every location in the image | https://huggingface.co/datasets/fmars/wiki_stem |
An inductively coupled plasma (ICP) or transformer coupled plasma (TCP) is a type of plasma source in which the energy is supplied by electric currents which are produced by electromagnetic induction, that is, by time-varying magnetic fields.
Operation
There are three types of ICP geometries: planar (Fig. 3 (a)), cylindrical (Fig | https://huggingface.co/datasets/fmars/wiki_stem |
Infrared photodissociation (IRPD) spectroscopy uses infrared radiation to break bonds in ions, (photodissociate), within a mass spectrometer. IRPD spectroscopy has been shown to use electron ionization, corona discharge, and electrospray ionization to obtain spectra of volatile and nonvolatile compounds. Ionized gases trapped in a mass spectrometer can be studied without the need of a solvent as in infrared spectroscopy | https://huggingface.co/datasets/fmars/wiki_stem |
The Inglis–Teller equation represents an approximate relationship between the plasma density and the principal quantum number of the highest bound state of an atom. The equation was derived by David R. Inglis and Edward Teller in 1939 | https://huggingface.co/datasets/fmars/wiki_stem |
Internal conversion is a transition from a higher to a lower electronic state in a molecule or atom. It is sometimes called "radiationless de-excitation", because no photons are emitted. It differs from intersystem crossing in that, while both are radiationless methods of de-excitation, the molecular spin state for internal conversion remains the same, whereas it changes for intersystem crossing | https://huggingface.co/datasets/fmars/wiki_stem |
In chemistry, intervalence charge transfer, often abbreviated IVCT or even IT, is a type of charge-transfer band that is associated with mixed valence compounds. It is most common for systems with two metal sites differing only in oxidation state. Quite often such electron transfer reverses the oxidation states of the sites | https://huggingface.co/datasets/fmars/wiki_stem |
The isomeric shift (also called isomer shift) is the shift on atomic spectral lines and gamma spectral lines, which occurs as a consequence of replacement of one nuclear isomer by another. It is usually called isomeric shift on atomic spectral lines and Mössbauer isomeric shift respectively. If the spectra also have hyperfine structure the shift refers to the center of gravity of the spectra | https://huggingface.co/datasets/fmars/wiki_stem |
Isotopic labeling (or isotopic labelling) is a technique used to track the passage of an isotope (an atom with a detectable variation in neutron count) through a reaction, metabolic pathway, or cell. The reactant is 'labeled' by replacing specific atoms by their isotope. The reactant is then allowed to undergo the reaction | https://huggingface.co/datasets/fmars/wiki_stem |
JCAMP-DX are text-based file formats created by JCAMP for storing spectroscopic data. It started as a file format for Infrared spectroscopy. It was later expanded to cover Nuclear magnetic resonance spectroscopy, mass spectrometry, electron magnetic resonance and circular dichroism spectroscopy | https://huggingface.co/datasets/fmars/wiki_stem |
Kerr frequency combs (also known as microresonator frequency combs) are optical frequency combs which are generated from a continuous wave pump laser by the Kerr nonlinearity. This coherent conversion of the pump laser to a frequency comb takes place inside an optical resonator which is typically of micrometer to millimeter in size and is therefore termed a microresonator. The coherent generation of the frequency comb from a continuous wave laser with the optical nonlinearity as a gain sets Kerr frequency combs apart from today’s most common optical frequency combs | https://huggingface.co/datasets/fmars/wiki_stem |
Kreft's dichromaticity index (DI) is a measure for quantification of dichromatism. It is defined as the difference in hue angle (Δhab) between the color of the sample at the dilution, where the chroma (color saturation) is maximal, and the color of four times more diluted (or thinner) and four times more concentrated (or thicker) sample. The two hue angle differences are called the dichromaticity index towards lighter (Kreft's DIL) and
dichromaticity index towards darker (Kreft's DID) respectively | https://huggingface.co/datasets/fmars/wiki_stem |
In physics, the Lamb–Mössbauer factor (LMF, after Willis Lamb and Rudolf Mössbauer) or elastic incoherent structure factor (EISF) is the ratio of elastic to total incoherent neutron scattering, or the ratio of recoil-free to total nuclear resonant absorption in Mössbauer spectroscopy. The corresponding factor for coherent neutron or X-ray scattering is the Debye–Waller factor; often, that term is used in a more generic way to include the incoherent case as well.
When first reporting on recoil-free resonance absorption, Mössbauer (1959) cited relevant theoretical work by Lamb (1939) | https://huggingface.co/datasets/fmars/wiki_stem |
Laser diffraction analysis, also known as laser diffraction spectroscopy, is a technology that utilizes diffraction patterns of a laser beam passed through any object ranging from nanometers to millimeters in size to quickly measure geometrical dimensions of a particle. This particle size analysis process does not depend on volumetric flow rate, the amount of particles that passes through a surface over time.
Fraunhofer vs | https://huggingface.co/datasets/fmars/wiki_stem |
Linear dichroism (LD) or diattenuation is the difference between absorption of light polarized parallel and polarized perpendicular to an orientation axis. It is the property of a material whose transmittance depends on the orientation of linearly polarized light incident upon it. As a technique, it is primarily used to study the functionality and structure of molecules | https://huggingface.co/datasets/fmars/wiki_stem |
Littrow expansion and its counterpart Littrow compression are optical effects associated with slitless imaging spectrographs. These effects are named after austrian physicist Otto von Littrow. In a slitless imaging spectrograph, light is focused with a conventional optical system, which includes a transmission or reflection grating as in a conventional spectrograph | https://huggingface.co/datasets/fmars/wiki_stem |
The magic angle is a particular value of the collection angle of an electron microscope at which the measured energy-loss spectrum "magically" becomes independent of the tilt angle of the sample with respect to the beam direction. The magic angle is not uniquely defined for isotropic samples, but the definition is unique in the (typical) case of small angle scattering on materials with a "c-axis", such as graphite.
The "magic" angle depends on both the incoming electron energy (which is typically fixed) and the energy loss suffered by the electron | https://huggingface.co/datasets/fmars/wiki_stem |
Magnetic circular dichroism (MCD) is the differential absorption of left and right circularly polarized (LCP and RCP) light, induced in a sample by a strong magnetic field oriented parallel to the direction of light propagation. MCD measurements can detect transitions which are too weak to be seen in conventional optical absorption spectra, and it can be used to distinguish between overlapping transitions. Paramagnetic systems are common analytes, as their near-degenerate magnetic sublevels provide strong MCD intensity that varies with both field strength and sample temperature | https://huggingface.co/datasets/fmars/wiki_stem |
Mass-analyzed ion kinetic-energy spectrometry (MIKES) is a mass spectrometry technique by which mass spectra are obtained from a sector instrument that incorporates at least one magnetic sector plus one electric sector in reverse geometry (the beam first enters the magnetic sector). The accelerating voltage V, and the magnetic field B, are set to select the precursor ions of a particular m/z. The precursor ions then dissociate or react in an electric field-free region between the two sectors | https://huggingface.co/datasets/fmars/wiki_stem |
Matrix isolation is an experimental technique used in chemistry and physics. It generally involves a material being trapped within an unreactive matrix. A host matrix is a continuous solid phase in which guest particles (atoms, molecules, ions, etc | https://huggingface.co/datasets/fmars/wiki_stem |
Maximum entropy spectral estimation is a method of spectral density estimation. The goal is to improve the spectral quality based on the principle of maximum entropy. The method is based on choosing the spectrum which corresponds to the most random or the most unpredictable time series whose autocorrelation function agrees with the known values | https://huggingface.co/datasets/fmars/wiki_stem |
The McCumber relation (or McCumber theory) is a relationship between the effective cross-sections of absorption and emission of light in the physics of solid-state lasers. It is named after Dean McCumber, who proposed the relationship in 1964.
Definition
Let
σ
a
(
ω
)
{\displaystyle \sigma _{\rm {a}}(\omega )}
be the effective absorption cross-section
σ
e
(
ω
)
{\displaystyle \sigma _{\rm {e}}(\omega )}
be effective emission cross-sections at frequency
ω
{\displaystyle \omega }
, and let
T
{\displaystyle ~T~}
be the effective temperature of the medium | https://huggingface.co/datasets/fmars/wiki_stem |
Microspectrophotometry is the measure of the spectra of microscopic samples using different wavelengths of electromagnetic radiation (e. g. ultraviolet, visible and near infrared, etc | https://huggingface.co/datasets/fmars/wiki_stem |
Microwave spectroscopy is the spectroscopy method that employs microwaves, i. e. electromagnetic radiation at GHz frequencies, for the study of matter | https://huggingface.co/datasets/fmars/wiki_stem |
In theoretical chemistry, molecular electronic transitions take place when electrons in a molecule are excited from one energy level to a higher energy level. The energy change associated with this transition provides information on the structure of the molecule and determines many of its properties, such as colour. The relationship between the energy involved in the electronic transition and the frequency of radiation is given by Planck's relation | https://huggingface.co/datasets/fmars/wiki_stem |
In molecular physics, the molecular term symbol is a shorthand expression of the group representation and angular momenta that characterize the state of a molecule, i. e. its electronic quantum state which is an eigenstate of the electronic molecular Hamiltonian | https://huggingface.co/datasets/fmars/wiki_stem |
In physics and chemistry, motional narrowing is a phenomenon where a certain resonant frequency has a smaller linewidth than might be expected, due to motion in an inhomogeneous system. The discovery of motional narrowing has been attributed to Nicolaas Bloembergen during his thesis work in the 1940s
Example: NMR spectroscopy
A common example is NMR. In this process, the nuclear spin of an atom starts rotating, with the frequency of rotation proportional to the external magnetic field that the atom experiences | https://huggingface.co/datasets/fmars/wiki_stem |
Multi-parametric surface plasmon resonance (MP-SPR) is based on surface plasmon resonance (SPR), an established real-time label-free method for biomolecular interaction analysis, but it uses a different optical setup, a goniometric SPR configuration. While MP-SPR provides same kinetic information as SPR (equilibrium constant, dissociation constant, association constant), it provides also structural information (refractive index, layer thickness). Hence, MP-SPR measures both surface interactions and nanolayer properties | https://huggingface.co/datasets/fmars/wiki_stem |
Multiangle light scattering (MALS) describes a technique for measuring the light scattered by a sample into a plurality of angles. It is used for determining both the absolute molar mass and the average size of molecules in solution, by detecting how they scatter light. A collimated beam from a laser source is most often used, in which case the technique can be referred to as multiangle laser light scattering (MALLS) | https://huggingface.co/datasets/fmars/wiki_stem |
Multiple-pass or long path absorption cells are commonly used in spectroscopy to measure low-concentration components or to observe weak spectra in gases or liquids. Several important advances were made in this area beginning in the 1930s, and research into a wide range of applications continues to the present day.
Functional Overview
Generally the goal of this type of sample cell is to improve detection sensitivity by increasing the total optical path length that travels through a small, constant sample volume | https://huggingface.co/datasets/fmars/wiki_stem |
Multispectral imaging captures image data within specific wavelength ranges across the electromagnetic spectrum. The wavelengths may be separated by filters or detected with the use of instruments that are sensitive to particular wavelengths, including light from frequencies beyond the visible light range, i. e | https://huggingface.co/datasets/fmars/wiki_stem |
Multivariate optical computing, also known as molecular factor computing, is an approach to the development of compressed sensing spectroscopic instruments, particularly for industrial applications such as process analytical support. "Conventional" spectroscopic methods often employ multivariate and chemometric methods, such as multivariate calibration, pattern recognition, and classification, to extract analytical information (including concentration) from data collected at many different wavelengths. Multivariate optical computing uses an optical computer to analyze the data as it is collected | https://huggingface.co/datasets/fmars/wiki_stem |
A multivariate optical element (MOE), is the key part of a multivariate optical computer; an alternative to conventional spectrometry for the chemical analysis of materials.
It is helpful to understand how light is processed in a multivariate optical computer, as compared to how it is processed in a spectrometer. For example, if we are studying the composition of a powder mixture using diffuse reflectance, a suitable light source is directed at the powder mixture and light is collected, usually with a lens, after it has scattered from the powder surface | https://huggingface.co/datasets/fmars/wiki_stem |
Muon spin spectroscopy, also known as µSR, is an experimental technique based on the implantation of spin-polarized muons in matter and on the detection of the influence of the atomic, molecular or crystalline surroundings on their spin motion. The motion of the muon spin is due to the magnetic field experienced by the particle and may provide information on its local environment in a very similar way to other magnetic resonance techniques, such as electron spin resonance (ESR or EPR) and, more closely, nuclear magnetic resonance (NMR).
Introduction
Muon spin spectroscopy is an atomic, molecular and condensed matter experimental technique that exploits nuclear detection methods | https://huggingface.co/datasets/fmars/wiki_stem |
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