Saltiel J, Eaker DW. 1980. Lifetime and geometry of 1-phenyl-2-(2-naphthyl)ethene triplets: Evidence against the triplet mechanism for direct photoisomerization. Chem Phys Lett 75(2):209-213; doi: 10.1016/0009-2614(80)80498-2.
Abstract
Competitive azulene and oxygen quenching experiments demonstrate that the lifetime of 1-phenyl-2-(2-naphthyl)ethene (2-NPE) triplets, 104–150 ns, is much longer than ≈ 20 ns, the lifetime of a transient absorption previously assigned to them. The transient absorption is reassigned to the longer lived of two non-equilibrating isomeric excited transoid singlet states.