The structure of the Goldstein-Kaplan bands of N 2

Abstract

Three bands of the Goldstein-Kaplan system of N 2 have been photographed under high resolution and rotational analyses made. It is shown conclusively that the blue-green Goldstein bands and the ultra-violet Kaplan bands form a single system having the well-known B 3 Π g state as the lower level. The upper state, C' , is identified as 3 Π u with the rotational constants B 0 = 1·0496 cm -1 , D 0 = 10·9 x 10 -6 cm -1 , H 0 = 8·3 x 10 -10 cm -1 . The state shows case b coupling and has an unusual structure in which spin-spin interaction appears to play an important part. To account for the unusual properties of the state it is suggested that it arises from a mixture of two or more molecular orbital configurations. The vibrational structure indicates either that predissociation occurs or that the state has a small dissociation energy. The interaction of the C ´ and C states is discussed and is suggested to be responsible for the observed irregularities in the C 3 Π u state.