Abstract:
The absorption spectrum of F2CSe in the 18800-21900 cm-1 region has
been recorded at -770 C and 220 C under the conditions of medium resolution.
The responsible electronic promotion is TI* + n excitation which leads to 3A2
and lA2 excited states. Progressions in vI', v2', v3" v4' and v4" have been
identified in the spectrum and have been analyzed in terms of vibronic transitions
between a planar ground state and a nQnplanar excited state. The
- 3 - 1 - 1 - 1
origins of the a A2 + X Al and A A2 + X Al systems were assigned to the
bands at 19018 cm-l and 19689 cm-l . This has given a singlet-triplet splittl.
n g lA2 - 3A2 P f 671 cm -1 The out-of-plane wagging levels were found to
be anharmonic.
1 -1
Barrier heights of 2483 cm- and 2923 cm were obtained
for the lA2 and 3A2 upper states from a fitting of the energy levels of a
Lorentzian-quadratic function to the observed levels in the out-of-plane
wagging modes.
1 3
For the A2 and A2 states nonplanar equilibrium angles of
30.10 and 31.40 have been evaluated respectively.
i
