jp077108m_si_002.pdf (53.49 kB)
Download fileStimulated Emission Pumping Spectroscopyof the [X̃]A‘ State of CHF
journal contribution
posted on 24.01.2008, 00:00 authored by Calvin Mukarakate, Chong Tao, Christopher D. Jordan, William F. Polik, Scott A. ReidWe have recorded stimulated emission pumping (SEP) spectra of the Ã1A‘ ‘ → X̃1A‘ system of CHF, which
reveal rich detail concerning the rovibronic structure of the X̃1A‘ state up to ∼7000 cm-1 above the vibrationless
level. Using several intermediate Ã1A‘ ‘ state levels, we obtained rotationally resolved spectra for 16 of the 33
levels observed in our previous single vibronic level (SVL) emission study (Fan et al., J. Chem. Phys. 2005,
123, 014314), in addition to one new level. An anharmonic effective Hamiltonian model poorly reproduces
the term energies even with the improved set of data because of the extensive interactions among levels in
a given polyad (p) having combinations of ν1, ν2, ν3, which satisfy the relationship p = 2ν1 + ν2 + ν3.
However, the precise A rotational constants determined from the SEP data were invaluable in clarifying the
assignments for these strongly perturbed levels, and the data are well reproduced using a multiresonance
effective Hamiltonian model. The derived vibrational parameters are in good agreement with high level ab
initio calculations. The experimental frequencies were combined with those of CDF to derive a harmonic
force field and average (rz,) structures for the ground state.