Contributions of different electronic states to Raman scattering have been
studied by critical analyses of Raman excitation profiles of several normal
modes of vibration of biphenyl. In this context, the possible structure an
d other interesting properties of the molecule in the excited electronic st
ates have been discussed. It is found that the first allowed transition to
the excited state occurs at 248 nm whose major geometry change involves CC
stretching vibrations, whereas, for the second allowed transition (correspo
nding to 205 nm) inter (i.e., substituent-sensitive) and intra (i.e., ring-
breathing) ring CC stretching and in plane CCH angle bending modes are impo
rtant. (C) 2000 Elsevier Science B.V. All rights reserved.