Sunghwan Kim - Spectroscopic investigations and potential energy surfaces of the ground and excited electronic states of 1,3-benzodioxan

Version 3

      Publication Details (including relevant citation   information):

      K. McCann, M. Wagner, A. Guerra, P. Coronado, J.R. Villarreal, J.   Choo, S. Kim,   and J. Laane;

      Journal of Chemical Physics,   2009131, 044302.



      The laser-induced fluorescence spectra (both fluorescence   excitation and dispersed fluorescence) of jet-cooled   1,3-benzodioxan along with its ultraviolet absorption spectra   have been recorded and analyzed in order to determine the   vibrational quantum levels in both the ground and S1 (π, π )   electronic excited states. A detailed energy map of the   vibrational levels involving the six lowest frequency vibrations   was established and utilized to better understand the structural   and conformational differences between the ground and excited   electronic states. The energies of more than a dozen vibrational   excited states involving the out-of-plane ring twisting (ν47) and   the out-of-plane ring bending (ν48) modes were determined for   both S 0 and S1 electronic states. Ab initio and density   functional theory (DFT) calculations were also carried out to   complement the experimental work. The data allowed   one-dimensional potential energy functions in terms of the   ring-twisting coordinate to be calculated. These show the   molecule to have a twisting angle of 33° and a barrier to   planarity of 4300±500 cm-1 for the S0 ground state and an angle   of 24° and a barrier of 1500±200 cm-1 for the S 1 (π, π ) excited   state.


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