Isotope Shifts and the Vibrational Structure in Some Weaker Systems of N2

Abstract

The emission spectrum of ¹⁵N₂ has been studied in the region 2000–9000 Å with a view to investigating the vibrational structure of some of the weaker systems. In the cases of the Herman infrared bands and the Gaydon—Herman green bands, it has been possible to decide between alternative vibrational schemes which have been suggested. Observations have also been made on the Goldstein—Kaplan and the B′→B systems. In the near‐ultraviolet spectrum it is shown that the h→a, s′→a, r′→a, m→a, and d→a progression all arise from upper levels with v>0. The possibility that some of these progressions may belong to a single system is discussed. The vibrational schemes for the fifth positive and Kaplan's first and second systems have been confirmed. Some new bands of ¹⁵N₂ corresponding apparently to hitherto unobserved transitions are reported.