THE MEASUREMENT OF THE INTEGRATED INTENSITY OF THE $\nu_{3}$ BAND OF $CH_{3}F$ BY THE USE OF A $CO_{2}$ LASER
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Date
1976
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Publisher
Ohio State University
Abstract
One of the most powerful far-infrared lasers found today is the $CH_{3}F$ $laser.^{1,2}$ The operation of this laser is achieved through optical pumping of the $^{Q}Q(12,K) K = 1-7$ transitions of the $\nu_{3}$ band of $CH_{3}F$ by a $CO_{2}$ laser operating at the 9.55 $\mu$ - P(20) $line.^{2,3}$ The absorption coefficients of these transitions, which determine the optical pumping of the $CH_{3}F$ laser, have not been thoroughly measured and can be calculated from the integrated intensity of the $\nu_{3}$ band, $S_{b}$. The value of $S_{b}$ was obtained from the measured value of $\alpha\nu$, the absorption profile of the $^{Q}Q(12,K) K = 1,2$ transitions in this $\nu_{3}$ band, by the use of a semi-tunable $CO_{2}$ laser operating at the 9.55 $\mu$ - p(20) line. The spectral shape of $\alpha_{\nu}$ depends on three parameters: the mid-frequencies of these two transitions and $S_{b}$. Since the measured values of the mid-frequencies of the $^{Q}Q(12,1)$ and $^{Q}Q(12,2)$ transitions matched those found in the $literature,^{4}$ the value of $S_{b}$ was, thus, accurately measured. The value obtained $S_{b} = 619 \pm 28 cm^{-2} atm^{-1}$ is somewhat larger than that found in the $literature,^{5}$ $484 cm^{-2} atm^{-1}$. This result was confirmed by additional measurement of the average value of the absorption profile.
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$^{1}$ T. Y. Chang, T. J. Bridges, and E. G. Burkhardt, Appl. Phys. Lett. 17, 249 (1970). $^{2}$F. Brown, S. Kronheim, and E. Silver, Appl. Phys. Lett. 25, 394 (1974). $^{3}$R. J. Temkin, D. R. Cohn and Z. Drozdowicz, Opt. Communications 14 314 (1975). $^{4}$S. M. Freund, G. Duxbury, M. Romheld, J. T. Tiedje, and T. Oka, J. Mol. Spectrose. 52, 38 (1974). $^{5}$L. A. Gribov, ``Intensity Theory for Infrared Spectra of Polyatomic Molecules'', Consultant Bureau, New York, (1964).
Author Institution: Department of Chemistry, Cornell University
Author Institution: Department of Chemistry, Cornell University