Publications by authors named "A A Vigasin"

Detailed analysis of the unique broadband millimeter-wave (70-360 GHz) collision-induced absorption spectra in pure CO and in its mixture with Ar is presented. The nature of the observed continuum absorption is examined using classical trajectory simulation along with statistical physics consideration. Bimolecular continuum is decomposed in the phase space into separate contributions from the so-called free, quasibound, and true bound molecular pairs, the proportions of which greatly vary with temperature.

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This paper presents theoretical formalism and some results of the collision-induced absorption (CIA) spectral simulation based on the classical trajectory analysis. Our consideration relies on the use of ab initio potential energy and dipole moment surfaces for two interacting rigid monomers. Rigorous intermolecular Hamiltonian is represented and used in the body-fixed reference frame.

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This paper presents the systematic classical consideration of a statistical averaging procedure that permits the calculation of partition function, equilibrium constant, and some observables for polyatomic dimers composed of weakly interacting rigid monomers. It was shown that the number of independent internal coordinates in a body-fixed frame is a crucial parameter that largely determines the temperature dependence of the partition function irrespective of the kinematic coupling within various degrees of freedom. The kinetic energy was derived for the molecular pair of arbitrary complexity in the body-fixed frame.

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We report the results of an experimental study related to the relaxation of the nuclear spin isomers of the water molecule in a supersonic expansion. Rovibrational lines of both ortho and para spin isomers were recorded in the spectral range of HO stretching vibrations at around 3700 cm using FTIR direct absorption. Water vapor seeded in argon, helium, or oxygen or in a mixture of oxygen and argon was expanded into vacuum through a slit nozzle.

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