Redetermination of some of the spectroscopic constants of the electronic ground state of di‐Nitrogen 14N2, 14N15N and 15N2 using coherent anti‐stokes Raman spectroscopy

Calibrated coherent anti‐Stokes Raman (CARS) spectra have been recorded for the resolved Q branches of the vibrational fundamentals and first hot bands of 14N2, 14N15N and 15N2 at a temperature of 1200 K. The spectra show a convolved linewidth of 0.13 cm−1, and have been used to derive new values of spectroscopic constants, for the species observed, with specific reference to the position of the Q branch lines where J > 20 for v = 1–0, and J = 0–30 for v = 2–1. The critical overlap region of the fundamental and the hot band may now be computer simulated with confidence, which should be of considerable help in combustor thermometry using CARS.