Phys. Rev. Lett. 85, 2997 (2000)
N. Lorente and M. Persson,
Department of Applied Physics, Chalmers/Göteborg University, S-412 96
Göteborg, Sweden
We have developed a first-principles calculational method of vibrationally inelastic tunneling in the scanning tunneling microscopy. This method is based on density functional theory and Tersoff-Hamann theory for tunneling. The calculated values for the changes in tunneling conductance induced by the C-H (C-D) stretch modes of acetylene on copper and its spatial image for C-D mode are in good agreement with recent experiments. For the other vibrational modes we find much smaller changes primarily caused by a cancellation of elastic and inelastic contributions to the conductance.