Modelling laser-matter interactions for simple molecules

We consider the interaction of a molecule with an ultrashort laser pulse within the mean field approximation. A model has been generalized to treat the interaction of atomic hydrogen with an electromagnetic pulse. The kernel of the Coulomb potential in the momentum space is replaced by a sum of products of separable potentials supporting a bound state of the atom and built from the corresponding bound state wave function. The molecular orbitals are expressed in terms of gaussians and generated by means of a quantum chemistry software. We analyze the ionization yield as a function of the size of the gaussian basis for H₂ and H₂O molecules and the results are compared to those already existing in the literature. (paper)