# PRESSURE BROADENING AND SHIFT OF SOME $NH_{3}$ LINES MEASURED BY DIODE LASER SPECTROSCOPY

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 dc.creator Yamada, Koichi M. T. en_US dc.creator Fabian, M. en_US dc.creator Schieder, R. en_US dc.creator Winnewisser, G. en_US dc.date.accessioned 2006-06-15T15:30:43Z dc.date.available 2006-06-15T15:30:43Z dc.date.issued 1996 en_US dc.identifier 1996-RA-05 en_US dc.identifier.uri http://hdl.handle.net/1811/13489 dc.description Author Institution: National Institute for Advanced for Interdisciplinary Research; I. Physikalisches Institut, Universit\""{a}t zu en_US dc.description.abstract Using the stabilized diode laser spectrometer in Cologne we have precisely determined pressure-induced line broadening and line shift coefficients of six rovibrational transitions in the $v_{2}$ band of $NH_{3}$. Foreign gas effects due to $O_{2}$, $N_{2}$, $H_{2}O$, CO, He, and Ar have been investigated and the self-effects as well. The high accuracy in the frequency position of the laser was achieved by stabilizing the diode laser on an interference maximum of a Fabry-Perot interferometer of variable optical length. The laser frequency was swept by tuning the cavity length of the etalon: the cavity length was monitored by a stabilized HeNe laser. A simultaneous recording of an $NH_{3}$ spectrum with a reference cell at a fixed pressure has been introduced for an absolute calibration. The line positions relative to reference lines have been measured to a precision of 300 kHz. A good signal-to-noise ratio was achieved by using a Herriott-type multi-reflection cell with a total path length of 46.86 m. This allowed to use very small $NH_{3}$ partial pressures of the order of a few hundred $\mu$bar in the measurements of foreign gas effects to minimize the influence of $NH_{3}$ self-effects. It turned out that contamination of the gas sample with $H_{2}O$ imposed a serious upon the precise determination of the pressure effects, because of the large shift and broadening caused by $H_{2}O$. To remove any residual water contamination, the sample cell was connected to a cold finger submerged in a Dewar vessel filled with dry ice. The results of the present study are thus thought to be the most precise data of this kind now available. en_US dc.format.extent 132574 bytes dc.format.mimetype image/jpeg dc.language.iso English en_US dc.publisher Ohio State University en_US dc.title PRESSURE BROADENING AND SHIFT OF SOME $NH_{3}$ LINES MEASURED BY DIODE LASER SPECTROSCOPY en_US dc.type article en_US