Structure of the triplet excited state of tetrabromo-p-benzoquinone from time-resolved resonance Raman spectra and ab initio calculations

The triplet excited state of bromanil has been observed using time-resolved resonance Raman spectroscopy. Assignments of the bands have been made by c omparison with spectra of the ground state and of benzoquinone as well as i ts fluorinated and chlorinated analogues. The structure in the triplet exci ted state has been determined using ab initio calculations. The combined ex perimental and computed results confirm a greater degree of bond reorganiza tion in the tripler of bromanil compared to benzoquinone or fluoranil. (C) 2001 Elsevier Science B.V. All rights reserved.