| OVERTONE SPECTROSCOPY IN $CH_{4}$ AND $NH_{3}^*$ (1992) | |||||||||
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| *Work supported by the NASA Planetary Atmosphere Program (Grant NAGW-2387) and by NSF Grant CHE89-14953 to the G.R. Harrison Spectroscopy Laboratory. Author Institution: Department of Chemistry, and G.R. Harrison Spectroscopy Laboratory; Institute f\""{u}r Physikalische Chemie, Universit\""{a}t G\""{o}ttingen. Photoacoustic spectra of $CH_{4}$ and $NH_{3}$ in the three quanta region have been recorded using the first Stokes output of a Ti:sapphire laser Raman shifted by $H_{2}$ or $D_{2}$. The single-mode, narrow bandwidth radiation $(0.015 0.02 cm^{-1}$, 3-4 nsec pulse), together with the highly sensitive photoacoustic detection, provide exceptional quality spectra. Double resonance is being used lo make new spectroscopic assignments in these overtone bands. A tunable diode laser operating at $1300 cm^{-1}$ is used to probe assigned transitions in the $v_{4}$ fundamental while the Raman-shifted Ti:sapphire laser is scanned through the overtone band. The occurrence of a double resonance signal establishes the lower level rotational quantum numbers of the overtone transition. | |||||||||
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