Knowledge Bank

The time dependence of the microwave absorption of OCS and $NH3$ was measured under the on- and off-resonant conditions, utilizing Stark and source modulation, respectively. For OCS the effective pressure parameters obtained under the two conditions, which correspond, respectively, to ($T1-1+T2-1)/4\Pi P$ and ($T2\Pi P)-1$ according to the Bloch equation, are different beyond experimental error; the difference ($T2-1-T1-1)/2\Pi P$ is $0.94\pm 0,38(2.5\sigma$) MHz/Torr for $J=2\to 1$. This difference as also determined to be $1,19\pm 0.30$ MHz/Torr from the dependence of the nutation frequency on the microwave power. For the inversion transitions of $NH3$, the pressure broadening parameters $\Delta \nu p=(2\Pi T2P)-1$ were determined under off-resonant conditions and agreed with those obtained from line width measurement. Pressure Broadening Parameters:($Teff2\Pi P)-1$ MHz/Torr[FIGURE]