An efficient method for determining quantum dynamics in strong fields by integrating through amplitude and frequency parameter space

A new method which computes the dynamics of molecular systems under the influence of a strong field is presented. Eigenvalues and eigenfunctions of the time-dependent Schrِdinger equation are obtained and integrated over a range of field amplitudes and frequencies, and the evolution of the wavefunction is determined using Floquet formalism. With this method, it is possible to predict the wavefunction dynamics for an arbitrary range of field intensities and wavelengths by solving the time-dependent Schrِdinger equation only once or, in some cases, by not solving it at all, even though the field intensities are well within the nonperturbative regime. Large savings in computational time are demonstrated in application of the method to vibrational excitation of hydrogen fluoride.