Sunghwan Kim - Infrared, Raman, and ultraviolet absorption spectra and theoretical calculations and structure of 2,3,5,6-tetrafluoropyridine in its ground and excited electronic states

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      Publication Details (including relevant citation   information):

      H.-L. Sheu, P. Boopalachandran, S. Kim, and J. Laane;

      Chemical   Physics, 2015456, 28.



      Infrared and Raman spectra of 2,3,5,6-tetrafluoropyridine (TFPy)   were recorded and vibrational frequencies were assigned for its   S0 electronic ground states. Ab initio and density functional   theory (DFT) calculations were used to complement the   experimental work. The lowest electronic excited state of this   molecule was investigated with ultraviolet absorption   spectroscopy and theoretical CASSCF calculations. The band origin   was found to be at 35,704.6 cm-1 in the ultraviolet absorption   spectrum. A slightly puckered structure with a barrier to   planarity of 30 cm-1 was predicted by CASSCF calculations for the   S1(π, π∗) state. Lower frequencies for the out-of-plane ring   bending vibrations for the electronic excited state result from   the weaker π bonding within the pyridine ring.


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