Far-infrared collision-induced absorption in some compressed gaseous halogenated methanes

1985 ◽  
Vol 63 (4) ◽  
pp. 475-478 ◽  
Author(s):  
Nguyen- Van-Thanh ◽  
I. Rossi
Keyword(s):  
Reasonable Agreement ◽  
Far Infrared ◽  
Molecular Polarizability ◽  
Experimental Literature ◽  
Induced Absorption ◽  
Bimolecular Collisions ◽  
Halogenated Methanes

Calculations of the collision-induced rotational and translational absorptions have been performed for seven pure halogenated methanes CH3F, CH3Cl, CF3H, CF3Cl, CF3Br, CCl3H, and CCl3F. We have considered the theory of Frost for multipole-induced dipolar absorption in bimolecular collisions taking the anisotropy of the molecular polarizability into account. The comparison with experimental literature data of CF3H and CF3Cl was reported; a reasonable agreement was obtained only for CF3Cl.

Far-infrared collision-induced absorption in compressed gaseous polar linear molecules: application to N2O

1988 ◽  
Vol 66 (1) ◽  
pp. 7-10 ◽  
Author(s):  
Nguyen- Van-Thanh ◽  
I. Rossi
Keyword(s):  
Quadrupole Moment ◽  
Far Infrared ◽  
Pressure Data ◽  
Induced Absorption ◽  
A Value ◽  
Induced Dipole ◽  
Linear Molecules ◽  
Bimolecular Collisions ◽  
Integrated Intensities ◽  
Rotational Interaction

This paper deals with computations of the far-infrared collision-induced absorptions for polar linear molecules. We have considered Frost's theory for dipole- and quadrupole-induced dipole absorptions in bimolecular collisions, taking the anisotropy of the molecular polarizability into account. In addition to the induced rotational interaction, a translational effect may not be negligible. Detailed expressions for different contributions to the integrated intensities are reported for N2O. Using these calculated expressions and the moderately low pressure data, we have deduced a value for the quadrupole moment of N2O, [Formula: see text].

COLLISION-INDUCED ABSORPTION OF COMPRESSED GASES IN THE FAR INFRARED, PART I

1965 ◽  
Vol 43 (5) ◽  
pp. 729-750 ◽  
Author(s):  
D. R. Bosomworth ◽  
H. P. Gush
Keyword(s):  
Fourier Analysis ◽  
Infrared Absorption ◽  
Michelson Interferometer ◽  
Far Infrared ◽  
Gas Mixtures ◽  
Experimental Techniques ◽  
Rare Gas ◽  
Absorption Coefficients ◽  
Induced Absorption ◽  
Separate Paper

A study is being made of the far infrared absorption occurring in compressed rare-gas mixtures, and compressed homonuclear diatomic gases. The region investigated lies between 20 and 400 cm−1. The spectra are obtained from the Fourier analysis of interferograms produced by a dynamic Michelson interferometer. It is possible to obtain accurate absolute absorption coefficients for broad bands using this method provided care is exercised in the analysis of the interferograms. The necessary precautions are discussed in detail. The precision of the method obtained in practice is demonstrated using the far infrared bands of hydrogen and nitrogen as examples. Only the experimental techniques are discussed in this paper; the detailed results follow in a separate paper.

Pressure-induced absorption in nonpolar gases containing tetrahedral molecules

1976 ◽  
Vol 54 (5) ◽  
pp. 611-617 ◽  
Author(s):  
A. D. Buckingham ◽  
A. J. C. Ladd
Keyword(s):  
Dipole Moment ◽  
Field Gradient ◽  
Infrared Radiation ◽  
Far Infrared ◽  
Spectral Moment ◽  
Induced Absorption ◽  
Integrated Intensity ◽  
Tetrahedral Molecules ◽  
Spherical Molecule ◽  
Far Infrared Radiation

The theory of pressure-induced absorption of far infrared radiation by gases is extended to include the contribution of the dipole moment induced in a molecule by the field gradient due to its neighbours. This dipole is nonzero when the molecule lacks a centre of inversion, as in a tetrahedron. In the collision of two tetrahedra, the dipole induced in molecule 2 by the electric field of the octopole moment Ω1 of the partner leads to transitions in which ΔJ(1) = 0, ± 1, ±2, ±3, and ΔJ(2) = 0. The dipole induced by the field gradient of Ω1 leads to ΔJ(1) = 0, ±1, ±2, ±3, and ΔJ(2) = 0, ±1, ±2, ±3, and therefore gives a required increase in absorption at higher frequencies. The field-gradient contribution vanishes in a collision involving a tetrahedral and a spherical molecule. General expressions are given for the field-gradient contributions to the integrated intensity and to the −2 spectral moment.

Far-infrared interaction-induced absorption spectra of CS2C6H6 liquid mixtures

1992 ◽  
Vol 168 (2-3) ◽  
pp. 349-356 ◽  
Author(s):  
Evangelos Zoidis ◽  
Jannis Samios ◽  
Thomas Dorfmüller
Keyword(s):  
Absorption Spectra ◽  
Far Infrared ◽  
Liquid Mixtures ◽  
Induced Absorption

Collision-induced absorption in nitrogen at low temperatures

1985 ◽  
Vol 63 (5) ◽  
pp. 625-631 ◽  
Author(s):  
I. R. Dagg ◽  
A. Anderson ◽  
S. Yan ◽  
W. Smith ◽  
L. A. A. Read
Keyword(s):  
Quadrupole Moment ◽  
Laser System ◽  
Far Infrared ◽  
Microwave Cavity ◽  
Jones Potential ◽  
Induced Absorption ◽  
Line Shapes ◽  
Theoretical Predictions ◽  
Theoretical Line

The collision-induced absorption (CIA) spectrum for nitrogen has been measured in the spectral region below 360 cm−1 at 126, 149, 179, and 212 K. The measurements have been obtained using Fourier transform infrared (FTIR) techniques, a far infrared (FIR) laser system operating at 84.2 and 15.1 cm−1, and microwave cavity techniques. The experimental line shapes have been compared with the theoretical predictions of Joslin, based on Mori theory, and of Joslin and Gray, based on information theory alone. The data have been used to determine the quadrupole moment employing various intermolecular potentials. One Lennard–Jones potential has resulted in a quadrupole moment of 1.51 B, the value that was used in generating the theoretical line shapes. These results, when combined with our forthcoming measurements on nitrogen mixed with methane and argon, may be helpful in determining the role of CIA in calculating the opacity of some planetary atmospheres.

Far‐Infrared Collision‐Induced Absorption in CO2. I. Temperature Dependence

1971 ◽  
Vol 55 (3) ◽  
pp. 1028-1038 ◽  
Author(s):  
W. Ho ◽  
G. Birnbaum ◽  
A. Rosenberg
Keyword(s):  
Temperature Dependence ◽  
Far Infrared ◽  
Induced Absorption

Temperature dependent collision-induced absorption in nitrogen

1984 ◽  
Vol 62 (4) ◽  
pp. 338-347 ◽  
Author(s):  
N. W. B. Stone ◽  
L. A. A. Read ◽  
A. Anderson ◽  
I. R. Dagg ◽  
W. Smith
Keyword(s):  
Close Agreement ◽  
Far Infrared ◽  
Intermolecular Potential ◽  
Fourier Transform Spectrometer ◽  
Fir Laser ◽  
Complete Spectrum ◽  
Temperature Dependent ◽  
Induced Absorption ◽  
Different Temperatures ◽  
Microwave Data

The collision-induced rotational translational spectrum of gaseous N2 has been measured in the temperature range 228–343 K at six different temperatures. The measurements were made with a Fourier transform spectrometer in the 25 to 360 cm−1 region and at 15.1 and 84.2 cm−1 with far infrared (FIR) laser. Previously obtained microwave data at 2.3 and 4.7 cm−1 have been used in defining the complete spectrum. Using a recently developed theory for quadrupolar-induced absorption, we find that the calculated quadrupole moment is independent of temperature and has a magnitude in close agreement with the recommended values of several other workers; i.e., Q = 1.46 B. The calculated value depends on the particular form of the intermolecular potential and this dependence is examined in some detail. A contribution to the absorption originating primarily from hexadecapolar and overlap induction has been observed in agreement with theoretical estimates and leads to an estimated value for the hexadecapolar moment [Formula: see text].

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