Knowledge Bank

Vibration-rotation transition of $NH2$ in the $A~2A1$ state were observed with sub-Doppler resolution by using a dye laser and a $CO2/N2O$ laser combined with the laser magnetic resonance technique. The cw dye laser output (Rh 6G, 70 mW) was introduced into a fluorescence cell placed in the $CO2/N2O$ laser cavity through a ZnSe partial reflector. The infrared laser was modulated by an intracavity chopper, and the double resonance signal was observed as a change in fluorescence intensity by using a phase-sensitive detector. When the dye laser pumped the $A~2A1(090)22 0-X~2B1(000)11 0$ transition $29MJ$ components of $(0100)211-(090)22 0$ in {\AA} were observed by sweeping the magnetic field. An analysis of the observed spectra revealed a large change in the orbital magnetic g-factor along the a-axis, $g\ell aa$, between the $v2=9$ and 10 vibrational state: -0.1246 (39) and -0. 0506(55) in (090) and (0 10 0), respectively. Three additional lines which corresponded to changes in fluorescence intensity opposite in sign to those for the 29 M components mentioned above, were also observed and tentatively assigned to transition from $A~2A1$ (090) to a highly excited vibrational state of $X~$.