Time-Delayed Li, Be, and B Autoionization Spectra Excited in Low-Energy (200 keV) Single Gas Collisions

Abstract

Metastable, autoionizing high-spin states are studied using the ion-beam time-of-flight method in connection with single-collision excitation. High-resolution, time-delayed spectra are obtained from Li, Be, and B excited in 200-keV impact on C${\mathrm{H}}_4$ Evidence is found for the $\left(1s2s2\mathrm{}{p}^2\right){}_{}{}^5{}_{}{}^{}P$ state in B ii. Excitation energies for the observed quartet and quintet states are given, and the branching ratio associated with the B ii $\left(1s2s2\mathrm{}{p}^2\right){}_{}{}^5{}_{}{}^{}P$ decay is estimated.