On the two-photon ionization of atomic caesium: electric-dipole plus quadrupole approximation

Abstract
Calculations of the two-photon ionisation probability rates of atomic caesium are reported for incident photon energies between 19400 and 22000cm-1. In this work the authors have taken into account the electric-dipole plus quadrupole approximation. The discrepancy between the theoretical results and experimental measurements is not explained in spite of the introduction of the quadrupole contribution as was suggested elsewhere.