New observations and analyses of highly excited bands of the fourth-positive [formula omitted] band system in [formula omitted

Abstract

In the emission spectrum of the CO molecule thirteen bands of the fourth-positive (A1Π→X1Σ+) band system were photographed and analysed. Under high resolution and by using conventional photographic spectroscopy, the following excited bands: 7–16, 7–17, 8–18, 8–19, 9–19, 9–20, 10–20, 10–21, 11–21, 11–22, 12–22, 13–24, 14–26 and approximately 1340 molecular lines were recorded. A rotational analysis of the bands: 7–17, 8–18, 8–19, 9–20, and 11–22 were carried out for the first time, and the bands 11–21 and 14–26 were identified and analysed for the first time. After detailed rotational analysis of the bands, experimental rovibronic term values of the A1Π (v=9–14) levels were determined for the first time. Individual and equilibrium molecular constants of the A1Π state as well as the Franck–Condon factors were determined for the analysed bands. Moreover, a region of analysed perturbations of the A1Π (v=7–14) levels was extended to the J⩾30 rotational levels. Also, most of theoretically predicted perturbations of the vA=13 and 14 levels were identified for the first time.