Download or read book Collision induced Absorption in Gases written by Lothar Frommhold and published by . This book was released on 1993 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reviews the theory and experiment of collision-induced absorption of infrared radiation in dense gases.
Download or read book Collision induced Absorption of Compressed Gases in the Very Far Infrared written by Douglas R. Bosomworth and published by . This book was released on 1964 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Phenomena Induced by Intermolecular Interactions written by G. Birnbaum and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is concerned with recent experimental and theoretical work dealing with phenomena created by the transient dipoles and polarizabilities produced by intermolecular interactions. The for mer produce absorption from the microwave to the optical regions of the spectrum and the latter produce Rayleigh and Raman scattering; such absorption and scattering would be absent without collisions. Static properties, such as dielectric constant, refractive index, and Kerr effect, also exhibit the effects of induced dipoles and polarizabilities. The first observation of an infrared absorption spectrum pro duced by the collisions of molecules which ordinarily do not have an allowed dipole transition was reported in 1949 (Crawford, Welsh, and Locke). The first observation of depolarized Rayleigh spectra due to collisions in atomic gases appeared in 1968 (McTague and Birnbaum). However, it was not until 1977 that the first conference dealing with collision-induced phenomena was organized by J. D. Poll at the University of Guelph. This conference was mainly concerned with studies of collision-induced absorption in gases. Light scat tering received more attention at the second meeting of the colli sion-induced community in 1978, at the E. Fermi Summer School on "Intermolecular Spectroscopy and Dynamical Properties of Dense Sys tems," organized by J. Van Kranendonk. However, the emphasis was still on collision-induced absorption in compressed gases, although some work on liquids, solid H , and related subjects such as ro 2 tational relaxation was included. The third induced phenomena con ference, organized by F.
Download or read book Collision and Interaction Induced Spectroscopy written by G.C. Tabisz and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 581 pages. Available in PDF, EPUB and Kindle. Book excerpt: Collision-or interaction-induced spectroscopy refers to radiative transitions, which are forbidden in free atoms or molecules, but which occur in clusters of interacting atoms or molecules. The most common phenomena are induced absorption, in the infrared region, and induced light scattering, which involves inelastic scattering of visible laser light. The particle interactions giving rise to the necessary induced dipole moments and polarizabilities are modelled at long range by multipole expansions; at short range, electron overlap and exchange mechanisms come into play. Information on atomic and molecular interactions and dynamics in dense media on a picosecond timescale may be drawn from the spectra. Collision-induced absorption in the infrared was discovered at the University of Toronto in 1949 by Crawford, Welsh and Locke who studied liquid O and N. Through the 1950s and 1960s, 2 2 experimental elucidation of the phenomenon, particularly in gases, continued and theoretical underpinnings were established. In the late 1960s, the related phenomenon of collision-induced light scattering was first observed in compressed inert gases. In 1978, an 'Enrico Fermi' Summer School was held at Varenna, Italy, under the directorship of J. Van Kranendonk. The lectures, there, reviewed activity from the previous two decades, during which the approach to the subject had not changed greatly. In 1983, a highly successful NATO Advanced Research Workshop was held at Bonas, France, under the directorship of G. Birnbaum. An important outcome of that meeting was the demonstration of the maturity and sophistication of current experimental and theoretical techniques.
Download or read book Collision induced Microwave Absorption in Compressed Gases written by J. L. Urbaniak and published by . This book was released on 1975 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Collision induced Absorption in Diatomic Molecule rare gas Mixtures written by H. T. Yura and published by . This book was released on 1967 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: A quantum mechanical calculation is given for collision-induced absorption in the infrared and far-infrared spectral regions for mixtures consisting of symmetrical diatomic molecules and rare-gas atoms. The induced moment consists of a short-range overlap term and a long-range quadrupole term. Near molecular transition lines, the quadrupole term gives the main contribution to the absorption, while in the far wings, the overlap term is dominant. The H2-He, H2-Ar, N2-Ar systems are considered, and an estimate is given of the absorption coefficient near 10 millimicrons for N2-N2 systems. (Author).
Download or read book A Theory of Collision induced Absorption and a Study of Gaseous written by Mary Moon and published by . This book was released on 1985 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Collision induced Absorption of Hydrogen Containing Systems written by Hua-Kuang Lee and published by . This book was released on 2020 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the Big Bang, hydrogen and helium were produced, with very small quantities of deuterium, tritium, and lithium. Due to gravitational attraction, the gases began to congregate. The conversion of gravitational potential energy to kinetic energy raised the temperature. For the gas clouds to continue to contract for form stars, some cooling mechanism was needed. In this thesis, ab initio calculations of collision-induced dipoles are reported, for use in evaluating collision-induced emission as a potential cooling mechanism during the formation of the first stars. In nonequilibrium conditions, molecular hydrogen and atomic hydrogen can coexist, so transient dipoles formed during collisions of molecular hydrogen with either molecular hydrogen or atomic hydrogen may contribute to cooling. The first stars that were formed in the universe are called Population III stars. This thesis includes calculations that are relevant to the observed radiative profiles of very old, very cool white dwarf stars. The detected radiation from the stars is a combination of the radiation from both the core and the stellar atmosphere. Radiation coming from the core may be absorbed by the atmosphere and then reemitted at a lower frequency. The core temperature and the radiative spectrum from the core can be evaluated by fitting the high-energy end of the spectrum with a black-body radiative profile. Often the radiative profile at lower energy does not fit the predicted profile, based on the core temperature. This is attributed to absorption in the stellar atmosphere, due to transient dipoles formed during collisions of hydrogen molecules with hydrogen atoms, helium atoms, or other hydrogen molecules.Due to the harsh conditions that are required for the existence of atomic hydrogen, experimental data collision-induced absorption involving atomic hydrogen is not available from experiment. Also, results at very high temperatures are not available from experiment. The collision-induced dipoles and collision-induced absorption spectra must be determined through computational work. The interest in atomic hydrogen for the astrophysical applications leads to the three research projects that are described in this thesis: 1) the dipole moment of the H2-H system in various configurations, 2) the energy and dipole moment of equilateral/isosceles triangular H3, and 3) the correlation energy and dipole of He-H.This thesis contains high-level ab initio computational results for all three projects, obtained with comparatively large basis sets. The results for H2-H are the best available. The collision-induced dipole has been expressed as a series in the spherical harmonics of the H2 bond vector and the intermolecular vector for various bond lengths and intermolecular separations. The calculated coefficients in this series are reported, and it is shown that the coefficients converge to the known analytical forms at long range. For H3, the energies of the three lowest states are reported as functions of the H-H separation and vertex angle in equilateral and isosceles triangular configurations. The conical intersection is located. For He-H, the calculated correlation energies and the correlation contribution to the dipole are shown to match the known long-range forms very accurately. The leading sp-charge density matrix on H shows the predicted R7 behavior. It appears that larger basis sets are required to show the same behavior at the He center.
Download or read book Collision Induced Absorption in Diatomic Molecule written by Rand Corporation and published by . This book was released on 1965 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Collisional Effects on Molecular Spectra written by Jean-Michel Hartmann and published by Elsevier. This book was released on 2021-01-30 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gas phase molecular spectroscopy is a powerful tool for obtaining information on the geometry and internal structure of isolated molecules and their interactions with others. It enables the understanding and description, through measurements and modeling, of the influence of pressure on light absorption, emission, and scattering by gas molecules, which must be taken into account for the correct analysis and prediction of the resulting spectra. Collisional Effects on Molecular Spectra: Laboratory Experiments and Models, Consequences for Applications, Second Edition provides an updated review of current experimental techniques, theoretical knowledge, and practical applications. After an introduction to collisional effects on molecular spectra, the book moves on by taking a threefold approach: it highlights key models, reviews available data, and discusses the consequences for applications. These include areas such as heat transfer, remote sensing, optical sounding, metrology, probing of gas media, and climate predictions. This second edition also contains, with respect to the first one, significant amounts of new information, including 23 figures, 8 tables, and around 700 references. Drawing on the extensive experience of its expert authors, Collisional Effects on Molecular Spectra: Laboratory Experiments and Models, Consequences for Applications, Second Edition, is a valuable guide for all those involved with sourcing, researching, interpreting, or applying gas phase molecular spectroscopy techniques across a range of fields Provides updated information on the latest advances in the field, including isolated line shapes, line-broadening and -shifting, line-mixing, the far wings and associated continua, and collision-induced absorption Reviews recently developed experimental techniques of high accuracy and sensitivity Highlights the latest practical applications in areas such as metrology, probing of gas media, and climate prediction
Download or read book Collision Induced Dipole Moments written by T. F. Gallagher and published by . This book was released on 1984 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental studies of collision induced absorption of forbidden transitions have been conducted on Cs(6s sub 1 /2 - 5d sub 5/2), Na (nd sub 3/2 - nf sub 5/2) and Na (nd sub 3/2 - ng sub 7/2), n is greater than or = to 15. Perturbers utilized include heavy rare gases, molecular dipoles, and positive ions. A very strong enhancement of the forbidden Rydberg transitions in Na was observed and attributed to ionic space charge.
Download or read book Computational Investigations of Collision Induced Absorption written by Timothy Carl Lillestolen and published by . This book was released on 2005 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Collisional Effects on Molecular Spectra written by Jean-Michel Hartmann and published by Elsevier. This book was released on 2008-08-12 with total page 429 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gas phase molecular spectroscopy is a powerful tool for obtaining information on the geometry and internal structure of isolated molecules as well as on the interactions that they undergo. It enables the study of fundamental parameters and processes and is also used for the sounding of gas media through optical techniques. It has been facing always renewed challenges, due to the considerable improvement of experimental techniques and the increasing demand for accuracy and scope of remote sensing applications. In practice, the radiating molecule is usually not isolated but diluted in a mixture at significant total pressure. The collisions among the molecules composing the gas can have a large influence on the spectral shape, affecting all wavelength regions through various mechanisms. These must be taken into account for the correct analysis and prediction of the resulting spectra. This book reviews our current experimental and theoretical knowledge and the practical consequences of collisional effects on molecular spectral shapes in neutral gases. General expressions are first given. They are formal of difficult use for practical calculations often but enable discussion of the approximations leading to simplified situations. The first case examined is that of isolated transitions, with the usual pressure broadening and shifting but also refined effects due to speed dependence and collision-induced velocity changes. Collisional line-mixing, which invalidates the notion of isolated transitions and has spectral consequences when lines are closely spaced, is then discussed within the impact approximation. Regions where the contributions of many distant lines overlap, such as troughs between transitions and band wings, are considered next. For a description of these far wings the finite duration of collisions and concomitant breakdown of the impact approximation must be taken into account. Finally, for long paths or elevated pressures, the dipole or polarizability induced by intermolecular interactions can make significant contributions. Specific models for the description of these collision induced absorption and light scattering processes are presented. The above mentioned topics are reviewed and discussed from a threefold point of view: the various models, the available data, and the consequences for applications including heat transfer, remote sensing and optical sounding. The extensive bibliography and discussion of some remaining problems complete the text. State-of-the-art on the subject A bibliography of nearly 1,000 references Tools for practical calculations Consequences for other scientific fields Numerous illustrative examples Fulfilling a need since there is no equivalent monograph on the subject
Download or read book Analysis of the Absorption Profiles of the Collision induced Fundamental Band of H2 in H2 Xe H2 Kr and H2 Ar Mixtures written by Sambhunath Ghosh and published by . This book was released on 1971 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies of Collision induced Absorption Spectra with Long Paths at Low Temperatures written by Andrew Robert William McKellar and published by . This book was released on 1970 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of the Absorption Profiles of the Collision induced Fundamental Band of H2 in H2 Xe H2 Kr and H2 Ar Mixtures written by Sambhunath Ghosh and published by . This book was released on 1971 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Opacity written by Walter F. Huebner and published by Springer Science & Business Media. This book was released on 2014-01-02 with total page 582 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers all aspects of opacity and equations of state for gases, plasmas, and dust. The discussion emphasizes the continuous transformation of the equilibrium compositions of these phases as a function of temperature and density.
