Radiofrequency Spectroscopy Using Three-Level Maser Action

Abstract

A direct transition between l-type doublet of OCS molecule was observed either as emission or absorption using the three-level maser action. The pumping radiation was supplied by a klystron 2K33 at the frequency correspanding to J=2←1, and the l-type doubling transition at 12.78 Mc/sec for J=1 was observed by a modified Pound-Knight circuit. Generally the low frequency transition of molecules is shown to be detectable using the bandwidth of about 1 s⁻¹, if the corresponding microwave transition at 24,000 Mc/sec has the absorption coefficient larger than 10⁻⁸ cm⁻¹. The line-width can possibly be reduced to several kc/sec at the sacrifice of sensitivity. The application of this type of spectrometer is also discussed.