Abstract
Near-infrared DFB (distributed feedback) semiconductor lasers have been extensively applied to molecular spectroscopy for the first time. The overtone band of three isotopic species of HCN has been recorded from 6420 to 6590 cm−1 without any frequency gaps, and three hot bands of H12C14N have also been observed. The molecular constants of the observed bands and the dipole moment for the (0 00 2) state of H12C14N are obtained.