Author: Ching-Zhy KuoPublisher:
ISBN:
Category : Absorption spectra
Languages : en
Pages : 0
Book Description
Collision-induced 1st Overtone Infrared Absorption Band of Deuterium
Author: Ching-Zhy KuoPublisher:
ISBN:
Category : Absorption spectra
Languages : en
Pages : 0
Book Description
Collision-induced Absorption by Molecular Deuterium (D2) in the Rototranslational Band, the Fundamental Band, and the First Overtone Band of
Author: Martin Andreas AbelPublisher:
ISBN:
Category :
Languages : en
Pages : 264
Book Description
The electric charge distribution of molecules such as H2 and D2 is inversion-symmetric so that permanent dipole moments do not exist: such molecules are infrared-inactive. It is therefore interesting that gaseous, liquid, and solid hydrogen and its isotopes actually absorb infrared radiation, for example if gas densities are sufficiently high. The observed absorption arises from electric dipole moments induced by intermolecular interactions. It is of a supermolecular origin, due to binary (or higher-order) molecular complexes that may be transient (i.e., in a collisional encounter) or relatively stable (van-der-Waals molecule). Interaction-induced electric dipoles arise from the same mechanisms that generate the intermolecular forces: exchange forces, dispersion forces, and multipolar induction. Recently the induced dipole and potential energy surfaces of H2 pairs have been obtained by advanced quantum-chemical calculations. Interaction-induced absorption, more commonly called collision-induced absorption (CIA), by H2 pairs is an important opacity source in the atmospheres of various types of planets and cool stars, such as late stars, low-mass stars, brown dwarfs, certain white dwarfs, etc., and therefore of special astronomical interest. The emission spectra of cool white dwarf stars differ significantly from the expected blackbody spectra of their cores, mainly due to collision-induced absorption by collisional complexes of hydrogen and helium in the stellar atmospheres. Before proceeding to the frequencies and temperatures of interest it is good to check the new potential energy surface and induced dipole surface in all possible ways by comparison with existing isotopic laboratory measurements. Furthermore, the new potential energy surface is directly compared with previously available, well established intermolecular potential energy surfaces. The electric charge distributions of deuterium and hydrogen are very similar. The new potential energy and induced dipole surfaces were originally obtained to facilitate the computation of the collision-induced absorption of hydrogen. However, by replacing the rotovibrational wavefunctions of H2 with those of D2 the surfaces can also be used to calculate the collision-induced absorption of deuterium pairs, thereby probing them further. At the temperature of 298K existing measurements of the collision-induced absorption of D2--D2 gas are compared with our quantum scattering calculations in the D2 fundamental band (approximately 2,500cm−1 to 4,500cm−1). Furthermore, measurements of the collision-induced absorption of deuterium (D2) in the D2 first overtone band (about 5,250cm−1 to 7,250cm−1) at 201K are reported. These measurements are compared with ab initio calculations of the absorption spectra. Close agreement of measured and calculated spectra is seen.
Aspects of Collision-induced Absorption of Hydrogen and Deuterium
Author: Paul G. GillardPublisher:
ISBN:
Category : Deuterium
Languages : en
Pages : 290
Book Description
Abstracts - Symposium on Molecular Structure and Spectroscopy
Author: Collision-induced Infrared Absorption Spectra of the Fundamental Bands of Hydrogen Deuteride and Hydrogen
Author: Prasad, Ram Deo GopalPublisher: 1976.
ISBN:
Category : Absorption spectra
Languages : en
Pages : 314
Book Description
Collision-induced Infrared Absorption Spectra of the Fundamental Bands of Hydrogen Deuteride and Hydrogen
Author: Ram Deo Gopal PrasadPublisher:
ISBN:
Category : Absorption spectra
Languages : en
Pages : 0
Book Description
Diatomic molecules: A critical bibliography of spectroscopic data
Author: Pressure-induced Infrared Absorption of the Fundamental Band of Deuterium in D2-He and D2-Ne Mixtures at Different Temperatures
Author: Wilson Eric RussellPublisher:
ISBN:
Category : Absorption spectra
Languages : en
Pages : 170
Book Description
Collisional Effects on Molecular Spectra
Author: Jean-Michel HartmannPublisher: Elsevier
ISBN: 0128227362
Category : Science
Languages : en
Pages : 577
Book Description
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
Pressure-induced Infrared Absorption of the Fundamental Band of Deuterium in D2-He and D2-Ne Mixtures at Different Temperatures
Author: Wilson Eric RussellPublisher:
ISBN:
Category : Absorption spectra
Languages : en
Pages : 170
Book Description