Multiphoton absorption in anharmonic systems

We study the multiphoton absorption of the diatomic HF by time propagating a wave packet on the electronic potential under the action of a monochromatic laser field. We apply the pseudo-spectral splitoperator method for the propagation. We use different approximations for the potential and for the dipole function. We find that the quantitative details of the absorption spectrum are sensitive to the form of the dipole function. © 1992 John Wiley & Sons, Inc.