Rotationally resolved vibrational overtone spectra of jet-cooled methanol
- Ecole Polytechnique Federale de Lausanne (Switzerland); and others
Infrared-optical double resonance excitation permits the measurement of fully rotationally resolved vibrational overtone spectra of jet-cooled methanol up to the 6{nu}{sub OH} level. These weak transitions to high vibrational levels are detected using the technique of IR assisted photofragment spectroscopy (IRLAPS). The elimination of spectral congestion reveals splittings of the zeroth-order rovibrational levels that reflect vibrational coupling to dark background levels. Analysis of the overtone spectra as a function of the number of OH stretch quanta indicates the presence of a strong coupling between zeroth-order states with n{nu}{sub OH} and those with (n-1){nu}{sub OH} + V{sub CHasym.st.}. This coupling is most clearly manifest at the 5{nu}{sub OH} level where the OH stretch frequency is anharmonically shifted close to that of the CH asymmetric stretch frequency. Finer spectral splittings reflect the coupling of the mixed OH-CH stretch states with the rest of the vibrational bath. The most recent results using this technique for CH{sub 3}OH and its partially deuterated analogs will be discussed.
- OSTI ID:
- 437235
- Report Number(s):
- CONF-9606118--
- Country of Publication:
- United States
- Language:
- English
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