Rotationally resolved studies of S0 and the exciton coupled S1 /S2 origin regions of diphenylmethane and the d12 isotopologue

Published

December 9, 2008

Author(s)

Jaime Stearns, Aloke Das, Talitha Selby, Timothy Zwier, David F. Plusquellic

Abstract

Resonant two-photon ionization (R2PI) and dispersed fluorescence (DF) spectroscopy are used to examine the role of torsional motions in the electronic structure of diphenylmethane (DPM) near the exciton split S1 and S2 origins at 266 nm. Three of the four low frequency features in the fluorescence excitation spectrum of the S1 state are assigned to a butterfly motion of the two rings and the symmetric and anti-symmetric combinations of the ring torsional motions. The symmetric torsional ring mode forms a progression up to four quanta in excitation and up to six quanta have been observed in emission to S0. The fourth low frequency feature at +123 cm-1 is assigned to the S2 state which corresponds to the upper level of the exciton couplet. The DF spectrum of the +123 cm-1 band reveals emission to four members of the non-totally symmetric torsional ring combination. Theoretical predictions of the S0, S1 and S2 states as well as results from rotationally resolved studies of these states reported in a forthcoming article are used to assist in the interpretation of a number of anomalous features of the S2 state.

Citation

Journal of Chemical Physics

Volume

129

Pub Type

Journals

Keywords

exciton splitting, excitonic interactions, gas phase, low frequency torsional progressions, ultraviolet

Citation

Stearns, J. , Das, A. , Selby, T. , Zwier, T. and Plusquellic, D. (2008), Rotationally resolved studies of S0 and the exciton coupled S1 /S2 origin regions of diphenylmethane and the d12 isotopologue, Journal of Chemical Physics (Accessed March 3, 2025)