Extraction of accurate autionisation widths from the emission spectrum of doubly-excited He

The autoionisation width of the 2s2p ³P⁰ level in He I has been determined through measurements of the widths of three different optical transitions, namely 2s2p ³P⁰-2p3p ³P^e, 2s3p ³P⁰-'2p3p' ³D^e and 2s2p ³P⁰-'2p4p' ³D^e giving the results 7.12+or-0.12, 8.36+or-0.08 and 8.32+or-0.15 meV respectively. As a tentative explanation for the extra broadening of transitions with ³D^e states as initial states the authors suggest that ³D^e states but not ³P^e states have an unusually large fine-structure splitting.