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

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 CH/sub 4/. Evidence is found for the (1s2s2p/sup 2/)/sup 5/P state in B II. Excitation energies for the observed quartet and quintet states are given, and the branching ratio associated with the BII (1s2s2p/sup 2/)/sup 5/P decay is estimated.