Journal of Physical Chemistry A, Vol.110, No.4, 1478-1483, 2006
High resolution electronic spectra of anisole and anisole-water in the gas phase: Hydrogen bond switching in the S-1 state
Rotationally resolved S-1<- S-0 electronic spectra of anisole and its hydrogen bonded complex containing one water molecule have been obtained. The results provide evidence for an "in-plane" complex in which the water molecule is attached via two hydrogen bonds to the anisole molecule, a donor O-H --- O(CH3) bond and an acceptor H-O ---H(ring) bond. Analysis of the subbands that appear in the spectrum of the complex suggests that hydrogen bond "switching" occurs when the complex absorbs light. The former O-H --- O(CH3) bond is stronger in the ground (S-0) state, whereas the latter H-O --- H(ring) bond is stronger in the excited (SI) state. Dynamical consequences of this phenomenon are discussed.