Observation of the 2ν1 band of HN+2 with a 1.57 μm distributed feedback semiconductor laser

Abstract
Near‐infrared distributed feedback (DFB) semiconductor lasers have been employed for high‐resolution spectroscopy of molecular ions. Thirteen lines of the 2ν1 band of HN+2 have been observed from 6380 to 6405 cm−1. A least‐squares analysis was carried out to yield two molecular constants of the v1=2 state. The band origin determined agrees very well with an ab initio theoretical prediction.