Far-infrared permanent and induced dipole absorption of diatomic molecules in rare-gas fluids. I. Spectral theory

Abstract

Articles you may be interested inFarinfrared permanent and induced dipole absorption of diatomic molecules in raregas fluids. II. Application to the CO-Ar system J. Chem. Phys. 103, 9175 (1995); 10.1063/1.470028 Infrared spectra of diatomic polar molecules in raregas liquids. I. Spectral theory J. Chem. Phys. 91, 3435 (1989); 10.1063/1.456918 A quasiharmonic model calculation for two nonMarkovian farinfrared spectra of diatomic polar molecules in a rare gas liquid. I. Spectral theory A quasiharmonic model calculation for two nonMarkovian farinfrared spectra of diatomic polar molecules in a rare gas liquid. II. Correlation functions of the interaction and spectral application to a HCl-Ar solution J. Chem. Phys. 86, 4607 (1987); 10.1063/1.452735 Far infrared absorption of diatomic polar molecules in simple liquids and statistical properties of the interactions. I. Spectral theoryWe present a spectral theory for the far-infrared absorption spectrum of a very diluted solution of diatomic molecules in a rare-gas fluid, that includes permanent and induced contributions. The absorption coefficient is given as the convolution of a translational spectrum and a rotational spectrum. The former is described in terms of time correlation functions associated to the induced dipole moment. The latter is discussed on the basis of a model consisting of a quantum rigid rotor interacting with a thermal bath, making use of time correlation functions associated to the different anisotropic orders of the solute-solvent intermolecular potential. Non-Markovian and line mixing effects are taken into account. Explicit expressions for the five leading contributions of the induced dipole moment are given.

Estimation of the Interaction-Induced Effects on the Far-Infrared and Infrared Correlation Functions of HCl Dissolved in CCl4: A Molecular Dynamics Study

“…In this particular case, it is very interesting to compare our FIR results for the HCl/CCl 4 system with previous published theoretical ones for similar mixtures obtained by other groups. We mention, e.g., the far-IR absorption of the diluted mixtures of HCl, DCl dissolved in liquefied inert gases (Ar, Kr, and Xe) and liquid SF 6 , which have been investigated theoretically 26 (see also ref −19 in ref ). These studies have shown that the induced contributions must be considered in order to reproduce the FIR experimental absorption spectrum of such systems, especially at high densities.…”

Perspective: Non-conventional Force Fields for Applications in Spectroscopy and Chemical Reaction Dynamics

“…because the total charge (Q = 0) and the total molecular dipole µ = 0.048 ea 0 lead to two partial charges close to zero but with opposite sign. In order to describe the substantial molecular quadrupole moment [35][36][37] (Θ = −1.58 ea 2 0 ) either a third interaction site midway the two atoms can be included 38 or the two atoms are described by a distributed multipole expansion. 14,21,39,40 More generally, the electrostatic potential (ESP) around a molecule can be represented as a superposition of point charges (PC) and higher multipole (MTP) moments.…”