Chaotic effects in IR resonant molecular vibrational photodesorption.

Abstract

In this paper the process of IR resonant molecular vibrational photodesorption, applied to the system ${\mathrm{CH}}_{3}$F-NaCl, is treated in terms of a simple two-dimensional (2D) classical model. Desorbing trajectories are shown to undergo a chaotic motion. By using the transport theory in Hamiltonian systems, in the phase space spanned by the coordinates of molecule-surface bond (the other coordinate being the intramolecular vibrational excitation), the characteristic bottlenecks, which render IR photodesorption an infrequent event, are located, the rates through them are computed, and the time evolution of the system is followed up to all times. A comparison with results obtained from numerical simulations, which are shown to be impractical in most of the cases of physical interest, is presented.