The absorption spectrum of the (1, 0), (3, 1) and (4, 2) bands in the c3Σ g+– a3Σ u+ system of He 2 eximer

Abstract

The near-infrared absorption spectrum of He 2 has been recorded in the range of 12 090–13 300 cm −1 using the optical heterodyne concentration modulation spectroscopy. Fifty-nine He 2 spectral lines were assigned to the (1, 0), (2, 0), (3, 1) and (4, 2) bands in the c 3Σ g +– a 3Σ u + system and a non-linear least-squares fitting was performed to get the improved molecular constants for the levels ( υ = 1, 3 and 4) in the upper electronic state.