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

Applying the coincident detection of photoions and photoelectrons with femtosecond 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 the (A) over tilde (2)A(2) electronic state is characterized by spinorbit coupling to the (2)A(1) electronic state within 7 ps, the subsequent transition 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 assigned to the direct excitation of the (2)A(1) state. (C) 2001 Elsevier Science B.V. All rights reserved.