First detection of an ultraviolet transition in an ionized polycyclic aromatic hydrocarbon

摘要

We report the first measurement of a polycyclic aromatic hydrocarbon cation electronic transition in the ultraviolet spectral region. The UV excitation spectrum of the D_n-XD_0 transition of the perylene cation (C_(20)H_(12)~+) isolated in an argon matrix was pumped with tunable, coherent radiation and monitored using the vibronic bands of the D_1(~2B_(3g)) -> (~2A_u)D_0 system. The two component band peaks at 244 and 250.2 nm, close to the S_2(~1B_(3u)) <- (~1A_g)S_0 transition in neutral perylene.