The NO(a 4II) state: direct photoexcitation from the ground state

Spectroscopic measurements are made on the (11, 0) band of the NO(a 4II—X 2II) system. The NO is excited by the 208–209 nm output of an excimer-laser-pumped doubled dye laser. The a(v = 11) population is transferred by collisions with NO and He to doublet levels, from which radiation is seen at 250–260 nm. The doublet and quartet character of the lines is distinguishable by the different temporal behavior of their fluorescence. The lines are assigned using simulated spectra. This study constitutes the first measurement of NO(a−X) line positions.