A- and C-type bands in the infra-red spectrum of pyrrole

Abstract

The rotational fine structure of the 3ν1 and ν22 vibrations of pyrrole (C4H5N) have been recorded at 0.98 and 14 µm respectively. About 100 lines were measured in the 3ν1 and 120 in the ν22R- and P-branches. The analysis of the resolved fine structure and of the Q-branch contour yielded the following molecular constants (all in cm–1): A′= 0.304 5, B′= 0.298 5, C′= 0.151 22, ν0= 10 184.174 for 3ν1, and text-decoration:overlineB′= 0.301 4, ν0= 722.21 for ν22. The rotational levels of 3ν1 with 35 < J < 45 are perturbed and the fine structure is either weak or not observed in this range of J-values.