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DETERMINATION OF $T_{2}/T_{1}$ FOR $^{15}NH_{3}$ INVERSION TRANSITIONS BROADENED BY $H_{2}$

Please use this identifier to cite or link to this item: http://hdl.handle.net/1811/10273

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Title: DETERMINATION OF $T_{2}/T_{1}$ FOR $^{15}NH_{3}$ INVERSION TRANSITIONS BROADENED BY $H_{2}$
Creators: Amano, T.; Schwendeman, R. H.
Issue Date: 1977
Abstract: Precise measurement of power-broadened linewidths with a computer-controlled microwave spectrometer together with measurement of microwave power make it possible to determine the relaxation times $T_{1}$ and $T_{2}$. The method was previously shown to be effective by application to the measurement of the self-broadening of microwave lines of $OCS^{1}$ and $^{15}NH_{3}.^{2}$ The $^{15}NH_{3}$ gas was mixed with $H_{2}$ inside the sample cell. The spectra were taken at various mixing ratios that ranged from $38 (H_{2}:NH_{3})$ to 750 in order to examine the systematic change of $T_{2}/T_{1}$ values. The values for $T_{2}/T_{1}$ range from 1.01 for the (J = 1, K = 1) to 1.39 for the (J = 8, K = 7) transition, and are closer to one than the corresponding values for the self-broadened lines. This tendency may be explained by assuming that the ratio of the effectiveness of $\alpha$-type^{\prime\prime} collision-induced transitions ($\Delta J = \pm 1$) to that of $\beta$ -type^{\prime\prime} collision-induced transitions ($\Delta J = 0$) is greater for $H_{2}$ broadening than for self-broadening. This is especially true for lower J and K transitions, and is consistent with the observations in the four-level microwave-microwave double resonance experiment by Daly and $Oka.^{3}$^{\prime\prime}
URI: http://hdl.handle.net/1811/10273
Other Identifiers: 1977-TG-14
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