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.