Some New Emission Bands of theA1Π -X1Σ+System of CH+

Eight bands of the A 1 Π- X 1 Σ + system of CH + have been photographed in emission from a hollow cathode discharge lamp using a high resolution spectrograph. Bands involving the ν" = 2 and ν" = 3 levels of the ground state have been observed for the first time. The simultaneous analysis of the eight bands yields improved molecular constants for the CH + molecule. The excited state constants show small irregularities in their variation with ν, but the ground state constants are regular and the principal constants in cm -1 are: ω e = 2857.56, ω e χ e = 59.32 B e = 14.1766(3), α e = 0.4939(4), 10 3 D e = 1.373(3), where the error limits are 1σ.