THE SPIN-FORBIDDEN A (4)PI(NU=13-15) AND B(4)SIGMA(-)(NU=3)[-X(2)PI(NU=0) BANDS OF NITRIC-OXIDE - A NEW SCHEME FOR QUANTUM STATE-SPECIFIC HIGH-RESOLUTION KINETIC-ENERGY MEASUREMENTS

A new scheme for performing high-resolution kinetic energy measurements on single quantum states of NO is described. Laser excitation of the a (4) Pi(nu=13-15) and b 4 Sigma(-)(nu= 3)<--X (2) Pi(v=0) spin-forbidden bands has been used to produce NO a (4) Pi, either by direct excitation or after excitation to NO b (4) Sigma(-) followed by b-->a emission. The sensitivity is compared to previous experiments on CO, employing the forbidden Cameron system. In the course of these experiments, three previously unknown vibronic levels of the a (4) Pi state were observed for which high precision molecular constants have been obtained. The derived molecular constants have been used to construct a chemically accurate RKR potential for the a (4) Pi state to within 0.2 eV of the dissociation limit. In addition, the electric dipole moments for the a (4) Pi(nu=13-14) levels have been determined. By comparing the experimental results with two ab initio calculations, the polarity of the dipole moment of the a (4) Pi State at equilibrium separation could be determined. A set of supplementary molecular beam laser-induced fluorescence studies on the b (4) Sigma(-)(v=3)<--X (2) Pi(nu=0) band were also carried out. These allowed the fluorescence lifetime of b (4) Sigma(-)(nu=3) state to be obtained under collision-free conditions and the electronic origin of the quartet manifold to be determined within 0.03 cm(-1). (C) 1995 American Institute of Physics.