NOTE
Reinvestigation of the A 2 Π u -X 2 Σ + g (11, 5) and (12, 6) Bands of N + 2 by Optical Heterodyne Magnetic Rotation Enhanced Velocity Modulation Spectroscopy
The spectra of the A 2 u -X + g and B 2 + u -X 2 + g transitions of N + 2 have been studied intensively since the 1920's using various spectroscopic techniques (1-17). Recently, we remeasured the rovibronic spectrum of N + 2 in the visible region from 16 800 to 17 573 cm -1 as a test of optical heterodyne magnetic rotation enhanced velocity modulation spectroscopy (OH-MR-VMS) (18). Some new lines of the (12, 6) ( 12) and (11, 5) (10) bands of the A 2 u -X 2 + g transition and the (1, 5) (10) band of the B 2 + u -X 2 + g transition were observed, and the molecular constants of these three bands were refined after a careful analysis of the observed lines together with all the available and reliable transition lines reported in the literatures.
The OH-MR-VMS technique has been discussed in detail by Wang et al. (18). The technique combines velocity modulation spectroscopy with optical heterodyne detection and the Faraday magnetic rotation (MR) effect to effectively eliminate the laser amplitude noise and the interference from both the glow and the electric fluctuation of the ac discharge used to generate transient species. Dramatically increased sensitivity and the discrimination of charged or neutral and paramagnetic or nonparamagnetic species make the technique ideal for the