Evidence for the non-statistical population of the 1s2s2p4P metastable state by electron capture in 4 MeV collisions of B3+(1s2s 3S) with H2 targets

Abstract

We have revisited previously published data involving collisions of mixed 4MeV B3+(1s21S,1s2s3S) with H2 targets (Benis et al., 2002) in search of evidence for the non-statistical production of the 1s2s2p4P long-lived metastable state by single electron capture. Using our recently published method for the accurate determination of the effective solid angle of Auger decaying metastable projectile states in combination with knowledge of the 1s2s3S metastable beam fraction allowed us to determine the ratio R=4P/2P of 1s2s2p quartet to doublet production cross sections both formed by electron capture. Our present determination of R=2.8±0.5, clearly departs from the expected value of R=2 based on statistical spin recoupling arguments and thus provides evidence for the active presence of additional population mechanisms in a new collision system.