THE VISIBLE PHOTOACOUSTIC SPECTRA OF VAPOR-PHASE METHANE AND DEUTERATED METHANES AT 77 K

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 dc.creator Scherer, G. J. en_US dc.creator Lehmann, K. K. en_US dc.creator Klemperer, William en_US dc.date.accessioned 2006-06-15T14:50:13Z dc.date.available 2006-06-15T14:50:13Z dc.date.issued 1983 en_US dc.identifier 1983-TC'-06 en_US dc.identifier.uri http://hdl.handle.net/1811/11969 dc.description Author Institution: Department of Chemistry, Harvard University en_US dc.description.abstract We have constructed a longitudinally resonant photoacoustic cell which can be cooled to liquid nitrogen temperature. This cell has been used intracavity in our automated dye laser $spectrometer^{1}$ to obtain low temperature, Doppler-limited spectra in the visible. Working at 77 k has two advantages: first, the Doppler width is 1/2 of its room temperature value; second, the rotational partition function is about 8 times smaller (for nonlinear molecules). Both of these features improve normally congested spectra. We have taken spectra of the C-H stretching overtones of methane and of deuterated methanes in the visible. The low temperature spectrum of $CH_{4}$ shows Doppler-width features, although the spectrum is still very congested. We have also studied $CD_{3}H$ at both room temperature and at 77 K. At room temperature, the rotational analysis is complicated by overlapping bands, and by incompletely resolved K-structure. We will present a rotational analysis of the low temperature spectrumof $CD_{3}H$ which shows completely resolved structures. $^{1}$K.K. Lehmann, G.J. Scherer and W. Klemperer, J. Chem. Phys. 77. 2853 (1982). en_US dc.format.extent 88517 bytes dc.format.mimetype image/jpeg dc.language.iso English en_US dc.publisher Ohio State University en_US dc.title THE VISIBLE PHOTOACOUSTIC SPECTRA OF VAPOR-PHASE METHANE AND DEUTERATED METHANES AT 77 K en_US dc.type article en_US