Laser-induced fluorescence and phosphorescence of C-60 isolated in solid Ne

Laser-induced fluorescence spectrum of C-60 isolated in solid Ne with resolved vibronic lines was recorded with laser excitation at 355 nm or in the 585-645 nm region. The spectrum consists of progressions with spacings similar to 260 cm(-1), each separated by varied intervals from the origin at 15 648 cm(-1). The intervals 272, 412, 971, 1452, 1587, 2883, 2924, and 3023 cm(-1) correspond to various vibrational levels of g(u) and h(u) symmetry, or their combination with the a(g)(1) level, of the ground electronic state; the similar to 260 cm(-1) progression (with 272 cm(-1) as the first spacing) corresponds to the Jahn-Teller active h(g)(8) mode. When the Ne matrix was doped with Xe (1.2%), phosphorescence of C-60 was greatly enhanced. The spectrum exhibits a single progression with origin at 12 773 cm(-1) and spacings near 260 cm(-1); its lifetime at 5 K was approximately 90 mu s. The fluorescence excitation spectrum revealed progressions of spacings either similar to 180 or similar to 260 cm(-1) corresponding to excitation to two different singlet excited states, respectively. The first excited singlet and triplet states observed in this work are proposed to be A T-1(2g) and a T-3(2g), respectively. The second excited singlet state, proposed to be B T-1(1g), lies approximately 200 cm(-1) above the A T-1(2g) state.