Abstract
Well-known variational principles for second-order perturbation matrix elements are extended to higher-order multiphoton processes for atomic hydrogen. Numerical applications to two- and three-photon ionization of the hydrogen ground state provide results comparable to those of analytic calculations, even near intermedaite-state resonances, yet without the complications involved in summation over intermediate states. Extensions to multiphoton processes for many-electron atoms are discussed briefly.
- Received 14 April 1988
DOI:https://doi.org/10.1103/PhysRevLett.61.404
©1988 American Physical Society