[[alternative]]Theoretical studies of vibrational energy relaxation of X-H stretching modes on hydrogen covered silicon and diamond (100), (111) and (110) surfaces

[[abstract]]Molecular dynamics simulation for three simple hydrogen-covered silicon and diamond surfaces, (100), (111) and (110) surfaces, were carried out to calculate the vibrational energy relaxation rates of Si-H and C-H stretches based on Bloch-Redfield theory. The calculated lifetimes on these surfaces were found to be in good agreement with experiment results. Lifetime of Si-H stretching mode on the Si(100)-2x1:H surface was slightly shorter than the experiment result due to surface reconstruction of this surface. Compared with previous MD simulations, the lifetimes of C-H stretching modes on diamond surfaces do not differ significantly from previous results when different bulk potential energy form was used. Besides the computations of the lifetime at room temperature, the results at higher temperature are reported and discussed as well. The temperature dependence results can be described approximately by the temperature dependence based on the Fermi Golden Rule. Analysis of the power spectrum of the fluctuating force along Si-H bond and C-H bond suggested that the dominate energy relaxation pathway on Si(100) and C(100) surfaces is through the couplings to the neighbor Si-Si-H bends and C-C-H bends, respectively. Direct calculation of the energies for the C-H bonds and C-C-H bends at low temperature strongly supports this energy relaxation mechanism.