A simple configuration-interaction calculational procedure with a finite-${\mathit{L}}^2$-basis set constructed from B splines is presented and applied to a multiphoton ionization process. An initial application of this theoretical procedure to the four-photon nonresonant ionization Mg at 532 nm has led to excellent agreement with the experimental photoelectron angular distribution measurement. The atomic structure effects due to the multielectron interactions are also examined in detail.

• Received 22 February 1990

DOI:https://doi.org/10.1103/PhysRevA.41.5265