Knowledge Bank

Power-broadened lineshapes have been recorded for thirteen inversion transitions of $15NH3$ 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 $T2$ but also on the function $(T1/T2)(\mu \in o/h)2$ where $T1$ 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 $T1$ and $T2$. The values of $T2/T1$ for the thirteen transitions in $\mathrm{<mrow\; data-mjx-texclass="ORD">15</mrow>}NH3$ were found to be all greater than one, ranging from 1.1 to 1.6.