Application of a boson Hubbard model to vibrational dynamics in adsorbate layers.

I study the nature of the fundamental (n=0→1) and «hot-band» (1→2) optical-absorption spectra of vibrational modes in adsorbed layers, as probed by weak, time-delayed, ir pulses after the system has been pumped by a strong ir pulse. The discussion is based on a boson Hubbard model and the theoretical results compare favorably with experimental studies (transient ir spectroscopyl of vibrational dynamics in adsorbed layers