VIBRATIONAL-ENERGY RELAXATION OF SI-H STRETCHING MODES ON THE H SI(111)1X1 SURFACE/

The vibrational relaxation rate of an excited Si-H stretching mode on the ideally H-terminated H/Si (111) 1 x 1 surface is calculated using Bloch-Redfield theory combined with classical molecular dynamics. The calculated lifetime is found to be in good agreement with the experime ntal result. Analysis of the power spectrum of the fluctuating force a long the Si-H bond suggests that the dominant energy relaxation pathwa y for the v = 1 stretching state is through kinetic coupling to a stat e with three Si-Si-H bending quanta plus one phonon. The v = 2 state i s predicted to relax at a considerably higher rate.