THE 0–0 AND 1–0 BANDS OF THE A(3Πi)–X(3Σ−) SYSTEM OF NH

Abstract

NH molecules have been produced during the flash photolysis of HNCO, and the 0–0 and 1–0 bands of the A(³Π_i) ← X(³Σ⁻) system have been photographed in absorption in the third order of a 21-foot concave grating spectrograph. The intensity distribution in the bands showed that the molecules were approximately at room temperature. The lines of lowest J value are identified for 25 branches of the 0–0 band and 19 branches of the 1–0 band. The analysis of the 0–0 band leads to a correction of the published line assignments for this band. The spin splittings in both the A and X electronic states, and the A-doubling in the A state, are considered in detail. Wavelengths in air are given for lines of astrophysical interest.