Resonance Raman spectroscopy and theoretical study on the photodissociation dynamics of formanilide in S3 state

Resonance Raman spectra were obtained for formanilide (FA) in acetonitrile solution with 239.5- and 245.9-nm excitation wavelengths in resonance with the S-3 state, and density functional theory (DFT) was used to elucidate the electronic transitions and resonance Raman spectra of FA. The spectra indicate that, in the Franck-Condon region, photodissociation dynamics has a multidimensional character with the motions mainly along the C=O stretching nu(8), the ring C=C stretch nu(9), the NH wag and ring CCH in-plane bend nu(11), the NH wag and ring CCH in-plane bend nu(12), ring C C stretch and ring CCH in-plane bend nu(16), the NH wag and ring CCH in-plane bend nu(17), the ring CCH in-plane bend nu(18), and the ring trigonal bend nu(24). The excited-state dynamics of the S-3 state is discussed, and the results are compared with those previously reported for benzamide (BA) to examine the N- or C-terminal-substituted aromatic effect of the peptide bond. Copyright (C) 2010 John Wiley & Sons, Ltd.