A model for multiple photon excitation of molecular vibrational modes by an infrared laser field is developed. The closed semiclassical Heisenberg equations of motion for a periodically driven anharmonic oscillator with two degrees of freedom are derived. The equations for a free nonlinear oscillator with two degrees of freedom are shown to be integrable with solution in terms of Jacobian elliptic functions resulting in a strictly regular intermode exchange of energy. When illuminating the molecule by a periodic infrared laser field, the absorption may strongly depend on the values of the molecular and laser parameters. We find numerically that the molecule may absorb coherent laser light chaotically. A mechanism of the onset of Hamiltonian chaos in our system is studied, using Poincare sections.

Date Published: 29 May 2002
PDF: 8 pages
Proc. SPIE 4748, ICONO 2001: Fundamental Aspects of Laser-Matter Interaction and Physics of Nanostructures, (29 May 2002); doi: 10.1117/12.468931

Published in SPIE Proceedings Vol. 4748:
ICONO 2001: Fundamental Aspects of Laser-Matter Interaction and Physics of Nanostructures
Anatoly V. Andreev; Pavel A. Apanasevich; Vladimir I. Emel'yanov; Alexander P. Nizovtsev, Editor(s)