Laboratory Determination of the Frequencies of Possible Interstellar Lines of NO+

Abstract

The A¹Π–X¹Σ emission bands of NO⁺ have been photographed at high dispersion and, from the measurements of these spectra, the frequencies of lines which are likely to be of astronomical significance have been determined. The (J = 1)–(J = 0) transition of the lowest vibrational level of the X¹Σ state is found to lie at 119 187 ± 30 MHz. The constants of the A¹Π and X¹Σ states have been improved.