Ultrafast photochemistry in OClO molecules analyzed by femtosecond time-resolved photoelectron spectroscopy

Applying the coincident detection of photoions and photoelectrons with femt osecond time resolution we have analyzed the energetics and the dynamics of the ultrafast processes initiated by excitation of OClO molecules with 50 fs laser pulses at 398 nm. The major channel leading to the excitation of t he (A) over tilde (2)A(2) electronic state is characterized by spinorbit co upling to the (2)A(1) electronic state within 7 ps, the subsequent transiti on to the B-2(2) state within 250 fs and, finally, the fragmentation to ClO + O and Cl + O-2 within about 750 fs. A minor channel is tentatively assig ned to the direct excitation of the (2)A(1) state. (C) 2001 Elsevier Scienc e B.V. All rights reserved.