Chaos in Multiple-Photon Excitation of Molecules

Abstract

With use of a Hamiltonian model system to represent ir laser excitation of a molecule it is shown that chaos is a fundamental aspect of this physical process. On average the chaos leads to a fluence-dependent absorption which previously was attributed to rapid statistical equilibration of energy in the quasicontinuum and was modeled by population rate equations. The origin of the chaos is the interplay of the pump mode's anharmonicity and intramolecular energy transfer.