INTERACTION ANISOTROPY AND QUANTUM DYNAMICS FOR VIBRATIONALLY INELASTIC-COLLISIONS OF LIH((1)SIGMA) WITH HE(S-1)

The ab initio potential energy surface (PES) already computed for the title system is employed here to study the behaviour of the collisiona l energy transfer processes over a broad range of energies. The quantu m evaluation of rotationally and vibrationally inelastic partial integ ral cross sections is carried out under different angular momentum cou pling conditions and the results are closely analysed in terms of the specific features of the coupling PES. State-to-state rate constants f or excitation and relaxation processes are obtained in a broad range o f temperatures and the overall efficiency of the collisional energy tr ansfer is analysed. The cooperative effect between the rotational anis otropy and the vibrational excitations is clearly shown and discussed. (C) 1998 Published by Elsevier Science B.V. All rights reserved.