Lineshapes and dipole moments in collision-induced absorption

1981 ◽  
Vol 59 (10) ◽  
pp. 1544-1554 ◽  
Author(s):  
George Birnbaum ◽  
Michael S. Brown ◽  
Lothar Frommhold
Keyword(s):  
Dipole Moment ◽  
Dipole Moments ◽  
Empirical Models ◽  
Fundamental Theory ◽  
Potential Models ◽  
Induced Absorption ◽  
Induced Dipole ◽  
Substantial Error ◽  
Argon Mixture ◽  
Helium Neon

Wave mechanical lineshapes of collision-induced absorption spectra are computed for binary mixtures of argon with helium, neon, and krypton using theoretical dipole moments as input. Comparison with measured spectra shows satisfactory agreement except for the neon–argon mixture, for which either theory or measurement is seen to be in substantial error. Empirical models of the collision-induced dipole moment which reproduce the experimental spectra more closely than the fundamental theory are also given. Best agreement between computed and experimental lineshapes is obtained when potential models which are accurate in the repulsive region are used.

Theoretical Calculation of the Rototranslational Collision-Induced Absorption (CIA) Spectra in O2–O2 Pairs

2016 ◽  
Vol 230 (8) ◽  
Author(s):  
Mohamed S. A. El-Kader
Keyword(s):  
Room Temperature ◽  
Interatomic Potential ◽  
Dipole Moments ◽  
Full Range ◽  
Quantum Mechanical ◽  
Fundamental Theory ◽  
Induced Absorption ◽  
Induced Dipole ◽  
Good Agreement

AbstractQuantum mechanical lineshapes of collision-induced absorption (CIA) at room temperature are computed for gaseous molecular oxygen using theoretical values for induced dipole moments and new isotropic interatomic potential as input. Comparison with measured spectra of the rototranslational collision-induced absorption shows good agreement over the full range of frequencies. Empirical models of the dipole moment which reproduce the experimental spectra and the first two spectral moments more closely than the fundamental theory are also given. The quality of the present potential has been checked by comparing between calculated and experimental thermo-physical and transport properties over a wide temperature range, which are found to be in good agreement.

Spectral lineshapes of collision-induced absorption (CIA) using isotropic intermolecular potential for N2-CH4

2021 ◽  
Vol 21 (4) ◽  
pp. 1063-1078
Author(s):  
M.S.A. El-Kader ◽  
G. Maroulis ◽  
T. Bancewicz
Keyword(s):  
Potential Model ◽  
Dipole Moments ◽  
Molecular Nitrogen ◽  
Intermolecular Potential ◽  
Gaseous Mixtures ◽  
Induced Absorption ◽  
Induced Dipole ◽  
Different Temperatures ◽  
Experimental Absorption ◽  
Good Agreement

Quantum mechanical lineshapes of collision-induced absorption (CIA) at different temperatures are computed for gaseous mixtures of molecular nitrogen and methane using theoretical values for the induced dipole moments and intermolecular potential as input. Comparison with theoretical absorption spectra shows satisfactory agreement. An empirical model of the dipole moment which reproduces the experimental spectra and the first three spectral moments more closely than the fundamental theory, is also presented. Good agreement between computed and experimental absorption lineshapes is obtained when a potential model which is constructed from the thermophysical and transport properties is used.

Moment analysis in collision-induced absorption: Determination of a single parameter empirical model for the induced dipole moment of He-Ar gas mixtures

2021 ◽  
pp. 1-16
Author(s):  
M.S.A. El-Kader ◽  
G. Maroulis
Keyword(s):  
Dipole Moment ◽  
Empirical Model ◽  
Adjustable Parameter ◽  
Classical Physics ◽  
Induced Absorption ◽  
Induced Dipole ◽  
Absorption Determination ◽  
Ar Gas ◽  
Good Agreement

We present a method for the construction of a one-adjustable-parameter empirical model for the induced dipole moment. The method is based on classical physics principles and relies on the first three spectral moments of the collision-induced absorption spectra at various temperatures and new interaction potentials. In this work it is applied to the spectra of He-Ar mixtures. Our values are in good agreement with the available ab initio data. The profiles calculated with these models at various temperatures are in excellent agreement with experiment.

Theory of Intercollisional Interference Effects. IV. Does a Zero Minimum in Induced Absorption Imply the Proportionality of the Induced Dipole Moment to the Force?

1973 ◽  
Vol 51 (23) ◽  
pp. 2455-2458 ◽  
Author(s):  
J. Courtenay Lewis
Keyword(s):  
Dipole Moment ◽  
Lorentz Gas ◽  
Intermolecular Force ◽  
Interference Effects ◽  
Induced Absorption ◽  
Induced Dipole ◽  
Interference Minimum

We show that, within the limits of the theory of intercollisional interference effects developed for collision-induced absorption by a Lorentz gas in paper I of this series, an intercollisional interference minimum which goes precisely to zero implies that the induced dipole moment is exactly proportional to the intermolecular force.

Memory Effects in the Collision-Induced Spectra of Noble Gases in Liquid Argon

1971 ◽  
Vol 49 (22) ◽  
pp. 2870-2873 ◽  
Author(s):  
U. Buontempo ◽  
S. Cunsolo ◽  
G. Jacucci
Keyword(s):  
Dipole Moment ◽  
Dipole Moments ◽  
Low Frequency ◽  
Far Infrared ◽  
Liquid Argon ◽  
Low Frequencies ◽  
Line Shapes ◽  
Induced Dipole ◽  
Rapid Fall ◽  
The Difference

We have measured the far infrared absorption spectra of dilute solutions of helium and neon in liquid argon arising from collision-induced electric dipole moments. The two spectra consist of broad bands similar in shape peaked at 70 cm−1 (Ne–A) and 120 cm−1 (He–A). They are characterized by a long high-frequency tail and a rapid fall at low frequency. The reduced line shapes are compared taking into account the difference in the duration of the collision-induced dipole moment. At high frequencies the two curves are similar to those observed in the gas phase. Their departure from the gaseous spectra at low frequencies is attributed to a negative correlation of the dipole moment induced in successive repulsive interactions.

On the Theory of Collision-Induced Absorption in Rare Gas Mixtures

1971 ◽  
Vol 49 (7) ◽  
pp. 837-847 ◽  
Author(s):  
S. L. Brenner ◽  
D. A. McQuarrie
Keyword(s):  
Absorption Spectrum ◽  
Dipole Moment ◽  
Far Infrared ◽  
Gas Mixtures ◽  
Moment Function ◽  
Rare Gas ◽  
Induced Absorption ◽  
Induced Dipole ◽  
Calculated Equilibrium

The observed far-infrared collision-induced absorption of helium–argon mixtures is used to determine the parameters in an induced-dipole moment function of the form[Formula: see text]It is shown that, with this form of μ(r), the values of the constants μo, ρ, and c7 that are necessary to fit the first two moments of the observed absorption contour are in disagreement with the available theoretical values of these constants. Possible explanations for this disagreement are discussed in the paper. Finally, it is shown that if μ(r) were known, it is possible to obtain an excellent representation of the entire absorption spectrum from a knowledge of only the first three moments, which are easily calculated equilibrium quantities.

Energies and Electric Dipole Moments of the Bound Vibrational States of HN2+ and DN2+

2008 ◽  
Vol 73 (6-7) ◽  
pp. 873-897 ◽  
Author(s):  
Vladimír Špirko ◽  
Ota Bludský ◽  
Wolfgang P. Kraemer
Keyword(s):  
Dipole Moment ◽  
Nearest Neighbor ◽  
Energy Surface ◽  
Dipole Moments ◽  
Three Dimensional ◽  
Vibrational States ◽  
Spacing Distribution ◽  
Triatomic Molecules ◽  
Vibrational Levels ◽  
Different Levels

The adiabatic three-dimensional potential energy surface and the corresponding dipole moment surface describing the ground electronic state of HN2+ (Χ1Σ+) are calculated at different levels of ab initio theory. The calculations cover the entire bound part of the potential up to its lowest dissociation channel including the isomerization barrier. Energies of all bound vibrational and low-lying ro-vibrational levels are determined in a fully variational procedure using the Suttcliffe-Tennyson Hamiltonian for triatomic molecules. They are in close agreement with the available experimental numbers. From the dipole moment function effective dipoles and transition moments are obtained for all the calculated vibrational and ro-vibrational states. Statistical tools such as the density of states or the nearest-neighbor level spacing distribution (NNSD) are applied to describe and analyse general patterns and characteristics of the energy and dipole results calculated for the massively large number of states of the strongly bound HN2+ ion and its deuterated isotopomer.

scholarly journals DERIVATION OF GENERALIZED THOMAS–BARGMANN–MICHEL–TELEGDI EQUATION FOR A PARTICLE WITH ELECTRIC DIPOLE MOMENT

2013 ◽  
Vol 28 (29) ◽  
pp. 1350147 ◽  
Author(s):  
TAKESHI FUKUYAMA ◽  
ALEXANDER J. SILENKO
Keyword(s):  
Dipole Moment ◽  
Electromagnetic Fields ◽  
Electric Dipole Moment ◽  
Electric Dipole ◽  
Dipole Moments ◽  
Classical Equation ◽  
Spin Motion ◽  
Electric Dipole Moments ◽  
Momentum Direction ◽  
Telegdi Equation

General classical equation of spin motion is explicitly derived for a particle with magnetic and electric dipole moments in electromagnetic fields. Equation describing the spin motion relative to the momentum direction in storage rings is also obtained.

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