K-shell photoionization of ground-state Li-like boron ions [B ~(2 +)]: Experiment and theory

摘要

Absolute cross sections for the K-shell photoionization of ground-state Li-like boron [B~(2 +)(1s~22s ~2S)] ions were measured by employing the ion-photon merged-beams technique at the Advanced Light Source synchrotron radiation facility. The energy ranges 197.5-200.5 eV, and 201.9-202.1 eV of the [1s(2s2p)~3P]~2P~o and [1s(2s2p)~1P] ~2P~o resonances, respectively, were investigated using resolving powers of up to 17 600. The energy range of the experiments was extended to about 238.2 eV yielding energies of the most prominent [1s(2? n?′)]~2P~o resonances with an absolute accuracy of the order of 130 ppm. The natural linewidths of the [1s(2s2p)~3P] ~2P~o and [1s(2s2p)~1P] ~2P~o resonances were measured to be 4.8 0.6 meV and 29.7 2.5 meV, respectively, which compare favourably with theoretical results of 4.40 meV and 30.53 meV determined using an intermediate-coupling R-matrix method.