Atomic core polarisation influence on single and multiphoton processes in atomic caesium

Abstract

The quantum defect method, generalised to the spin-orbit coupling scheme, has been used to calculate the oscillator strengths of the principal series for atomic caesium, taking into account the core polarisation produced by the valence electron. The good agreement obtained with respect to experimentally measured values has led the authors to carry out new calculations of generalised two-photon ionisation cross sections for the atomic caesium 6S ground state with linearly and circularly polarised incident radiation in the deep minimum region, related to destructive interferences, near the intermediate 7P resonance. A theoretical method previously developed was used; excellent agreement was obtained with respect to recent experimental data. The degree of spin polarisation of the ejected electrons has been calculated in the same region of incident photon energy.