Knowledge Bank

A microwave double resonance experiment has been carried out by using Q-band microwave power of 10 Watts as the pumping radiation. The main results are summarized as follows. (1) The M-structure of the double resonance spectra has been observed for the $(440\leftarrow 431\leftarrow 422)$ scheme of ethylene oxide. For this experiment a device was employed to make a homogeneous microwave electric field in the cell. (2) ``Forbidden'' transitions $303\leftarrow 000$ in ethyl iodide, which have calculated absorption coefficients of $5\times 10-11cm-1(F=7/2\leftarrow 5/2)$ and $3\times 10-11cm-1(F=5/2\leftarrow 5/2)$, have been observed with a good signal to noise ratio by using a double resonance for the scheme $(404\leftarrow 303\leftarrow 000).1$ (3) Preferred collisional transitions have been observed by a double resonance of the four level schemes $(221\leftarrow 212,330\leftarrow 321)$ and $(221\leftarrow 212,321\leftarrow 312)$ in ethylene oxide. This kind of double resonance experiment will provide useful information on the intermolecular $interaction.2\mathrm{<mrow\; data-mjx-texclass="ORD">1,2</mrow>}$T. Oka, J. Chem. Phys., accepted.