Abstract

CO₂ laser-microwave double resonance (LMDR) spectroscopy with intense electric field was applied to ¹⁴NH₃ and ¹⁵NH₃. The three-level double resonance effect caused by the combination of a rovibrational transition in the v₂ band and an inversion transition in the ground state was observed. The applied electric field was calibrated with an accuracy of 10 ppm using the infrared-infrared double resonance signals of PH₃, which in turn were calibrated against the OCS dipole moment. In total, 76 and 37 LMDR signals originating from 24 and 16 inversion transitions in the range of J = 2-11 and K= 2-10 were observed for ¹⁴NH₃ and ¹⁵NH₃, respectively.

© 1986 Optical Society of America