Transition probabilities of molecular systems in the presence of time dependent electric fields

Analytical expressions for the transition probabilities of a molecular syst em interacting with a low intensity time dependent electric field are deriv ed in the present contribution. The molecular system is modeled as a quarti c anharmonic oscillator, where the interaction with the electric field is d escribed by the electric-dipole approximation. Using Lie algebraic techniqu es and typical states of quantum optics, we are able to obtain an approxima te analytical expression for the temporal evolution operator in the present model system. (C) 2000 Published by Elsevier Science B.V.