Coherence-converted population transfer FTMW-IR double resonance spectroscopy of CH$_{3}$OD in the asymmetric CH-Stretch Region
ORAL
Abstract
State-selected infrared spectra of jet-cooled CH$_{3}$OD in the asymmetric CH stretch region (2890-3020 cm$^{-1}$) were obtained using the E-species microwave transitions: 1$_{0}\leftarrow $1$_{-1}$ at 18.957GHz; 2$_{0}\leftarrow $2$_{-1}$ at 18.991GHz; and 3$_{0}\leftarrow$3$_{-1}$ at 19.005GHz. The title technique enables the facile assignment of complex torsion-rotation spectra with multiple interacting vibrational bands. The two asymmetric CH-stretch fundamentals ($\nu _{2}$: 3000.2 cm$^{-1}$ and $\nu _{9 }$: 2955.7 cm$^{-1}$) are analyzed along with about 15 additional bands in the region of the binary combinations of the CH bends (2890- 2950 cm$^{-1}$). The number of observed vibrational bands indicates that the CH stretch bright states couple first to the binary CH bend combinations, and then to higher order combinations of the normal modes. The $J\prime $-dependence of the rotational structure is regular, but the $K\prime $-dependence is complicated by multiple strong $K\prime $-dependent interactions between vibrational states.
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