Determination of the hyperfine structure of the B 2Π12 state of NO from quantum beat spectroscopy

An extensive set of hyperfine splittings for the first five vibrational states of the B 2Π12 state of the NO has been accurately measured using quantum beat spectroscopy. Absolute assignment of the quantum beat signals is achieved through a novel detuning technique which uses the relative signal intensities as the laser is scanned off the rotational line to determine the energy ordering of transitions within the spectral linewidth. The Frosch and Foley hyperfine parameters which are determined in fits to the data show smooth variations with vibrational level but are significantly different from the ground state.