Laboratory observation of hot bands of H3+

Abstract

The (2ν2,l=2←ν2), (2ν2,l= 0←ν2), and (ν1+ν2←ν 1) hot bands of H3+ were observed. The vibrationally hot ions were produced in a liquid nitrogen cooled 6 kHz ac discharge using gas mixtures of H2 and He. The spectra were detected in direct absorption using a newly extended tunable difference frequency spectrometer using both LiNbO3 and LiIO3 crystals as nonlinear optical elements. The range of this spectrometer is now ∼5300-∼1900 cm-1. The positions of the rovibrational transitions compare extremely well with the theoretical predictions of Miller and Tennyson. A vibrational temperature study of the discharge indicates a significant population inversion between the ν1 and ν2 levels. © 1990 American Institute of Physics.