PHOTOEXCITED C-60 - FRAGMENTATION AND DELAYED IONIZATION

We investigate two reaction channels of C-60, excited by a pulsed lase r at 355 nm: i) The relative and absolute yields of even-sized fragmen t ions are measured over a wide range of laser fluences. At low fluenc e we find a dramatic dependence of the abundance ratio of C-n-2(+) ver sus C-n(+). This result argues against the notion that unimolecular em ission of C-4 Or larger fragments contributes significantly to the pro duction of even-sized fragment ions. ii) We count the number of delaye d electrons emitted from C-60, or one of its products, after photo-exc itation. For high laser fluences, this number reaches a value of (2.6 +/- 1.1)% per photoexcited C-60. This sets a lower bound to the ratio of effective rate constants, k(e)(E)/Sigma k(j)(E*), where k(e) refer s to electron emission, and the sum in the denominator extends over al l reaction channels.