DETERMINATION OF $T_{2}/T_{1}$ FOR $^{15}NH_{3}$ TRANSITIONS BY ANALYSIS OF POWER-BROADENED LINESHAPES

Abstract

Power-broadened lineshapes have been recorded for thirteen inversion transitions of $15_{NH_{3}}$ with a computer-controlled microwave spectrometer. The line profiles were recorded for each transition at several sample pressures and microwave powers. The recorded points were found to fit very well to a theoretical line shape which depends not only on the polarization relaxation time $T_{2}$ but also on the function $(T_{1}/T_{2}) ({\mu}{\in}_{o}/h)^{2}$ where $T_{1}$ is the population relaxation time., $\mu$ is the dipole moment matrix element, and $\in_{o}$ is the amplitude of the electric field of the radiation. Therefore, by careful measurement of the microwave power it was possible to determine both $T_{1}$ and $T_{2}$. The values of $T_{2}/T_{1}$ for the thirteen transitions in $^{15}NH_{3}$ were found to be all greater than one, ranging from 1.1 to 1.6.