A Monte Carlo and transfer-matrix grid path-integral study of the vibrational structure of Br 2 in solid argon

Abstract

A transfer-matrix grip path-integral method recently proposed, has been used to study vibrational intramolecular potentials for the ground X( 1Σ 0+u) and excite B( 3Π 0+u) electronic states of a Br 2 molecule solvated in a matrix of argon. The Monte Carlo method has been used to generate the set of configurations for a mixed quantum-classical system, consisting of a Morse oscillator, coupled to the argon matrix, assumed as a classical microscopic environment. It has been verified that when compared to the gas phase, the intramolecular potentials in the argon matrix are modified in a non-negligible way. By including transitions over the discrete vibrational levels for the different electronic states of the diatomic molecule in the matrix, good agreement with the experimental results of Friedman, Rousseau and Bondybey for the red-shift of the absorption profile (AP) from the Raman excitation profiles (REP) is observed, suggesting that a discrete resonance Raman scattering process is involved.