Generalized Langevin equation approach for the rotational relaxation of a molecule trapped in a 3D crystal. II. Application to CO and CH3F in argon

A numerical integration of the Langevin equations connected to the motions of a diatomic molecule trapped in a rare gas matrix is performed using a Runge–Kutta procedure and a Monte Carlo–Metropolis sampling for the initial configurations of the so‐called primary system (cf. paper I). The rotational energy transfer from the molecule to the crystal is shown to strongly depend on the coupling between the molecule and the nearest‐neighbor (NN) atoms and also on the ability for these NN atoms to dissipate their energy into the bath. Several cases are discussed according to the values of the viscous terms describing the damping of the molecule rotation and translation and of the NN atom vibrations. The prolate CH3F molecule trapped in an argon matrix seems to relax more quickly its rotational energy than the nearly isotropic CO molecule. Special trajectory calculations, when the molecule is rotationally excited or in thermal equilibrium, are considered in order to study the well jump and the librational motion...

[1]  Anthony J Leggett,et al.  Influence of Dissipation on Quantum Tunneling in Macroscopic Systems , 1981 .

[2]  C. Girardet,et al.  The dynamics of van der Waals dimers trapped in monatomic solids, a simplified model , 1985 .

[3]  L. Raff,et al.  A phenomenological approach to the calculation of the diffusion coefficient for Si on Si(111) using classical trajectories , 1985 .

[4]  H. Dubost,et al.  Librational relaxation and IR line broadening of matrix isolated CO , 1979 .

[5]  J. Manz,et al.  The geometry and vibrational frequency shift of CO molecules in an argon matrix studied by force-field calculations , 1980 .

[6]  L. Young,et al.  Vibrational relaxation of CH3F in inert gas matrices , 1982 .

[7]  Estela Blaisten-Barojas,et al.  Libron–phonon coupling effect on the infrared absorption spectra of molecules trapped in matrices , 1985, The Journal of Chemical Physics.

[8]  C. Girardet,et al.  Generalized Langevin equation approach for the rotational relaxation of a molecule trapped in a 3D crystal. I. Theoretical considerations , 1987 .

[9]  C. Girardet,et al.  A two-dimensional model for the infrared and microwave spectrum of diatomic molecules trapped in monatomic crystals , 1982 .

[10]  A. Nitzan,et al.  Stochastic classical trajectory approach to relaxation phenomena. III. Comparison of trajectory results to quantum mechanical perturbation theory , 1983 .

[11]  S. Charles,et al.  Infra-red spectra of carbon monoxide in krypton and xenon matrices at 20°K , 1965 .

[12]  R. R. Ernst,et al.  Hydrogen transfer in double minimum potential: Kinetic properties derived from quantum dynamics , 1987 .

[13]  P. Wolynes.  Quantum Theory of Activated Events in Condensed Phases , 1981 .

[14]  J. Manz.  Rotating molecules trapped in pseudorotating cages , 1980 .