Rotational collisional narrowing in the NO fundamental Q branch, studied with cw stimulated Raman spectroscopy

Abstract
Self‐broadened NO Q‐branch spectra were obtained in the pressure region ∼20–100 kPa. We determined J‐ and Ω‐dependent pressure broadening coefficients. The observed collisional narrowing was fitted by means of a relaxation matrix theory, incorporating recent experimental and theoretical values of NO state‐to‐state rates. A ‘‘fitting law’’ representation of the state‐to‐state rates yielded good agreement with both the measured broadening coefficients and the observed spectrum.