Two-photon excitation of atomic oxygen

Abstract

A standard perturbation expansion in the atom-radiation-field interaction is used to calculate the two-photon excitation cross section for the $1s^{2}2s^{2}2p^4{}_{}{}^3{}_{}{}^{}P$ to $1s^{2}2s^{2}2p^3\left({}_{}{}^4{}_{}{}^{}S\right)3p{}_{}{}^3{}_{}{}^{}P$ transition in atomic oxygen. The lowest-order summation over bound and continuum intermediate states is handled by solving the equivalent inhomogeneous differential equation. Higher-order electron-correlation effects are also examined.