Experimental lifetime of the a1Δ electronically excited state of CH-

By repeatedly probing the a(1)Delta excited state and the X-3 Sigma(-) ground-state populations in a beam of CH- ions stored in a cryogenic ion-beam storage ring for 100 s, we extract an intrinsic lifetime of 14.9 +/- 0.5 s for this excited state. This is far longer than all earlier experimental and theoretical results, exposing large difficulties in measuring and calculating slow decays and the need for benchmark quality experiments.

Automated summary

This study investigates the lifetimes of the a(1)Delta excited state and the X-3 Sigma(-) ground-state in CH- ion beams. The experimental results show a significantly longer lifetime compared to previous research, highlighting the difficulties in measuring slow decays.