NO V-J VECTOR CORRELATIONS IN THE PHOTODISSOCIATION OF 2-CHLORO-2-NITROSOPROPANE

The correlation between the velocity and angular momentum vectors of the NO X2ΠΩ=1/2,3/2(v=0) fragment from the photodissociation of 2-chloro-2-nitrosopropane, CH3CCl(NO)CH 3, following excitation to the S1Ã 1A″ electronic surface is measured. The experiments are performed in a molecular beam and a scheme for detecting NO by polarized 1+1′ resonance-enhanced multiphoton ionization and pulsed-extraction time-of-flight mass spectrometry is described. The vector correlation is a function of the NO rotational state j, and the bipolar moment describing the correlation has a maximum value of β00(22)=-0. 13(±0.01) at j≈18.5-22.5, indicating a preferred perpendicular orientation of the NO angular momentum and velocity vectors. The correlation diminishes as j decreases. This result is consistent with impulsive dissociation from a barrier along the reaction coordinate on the T1ã 3A″ surface, previously postulated to produce the highest angular momentum states of NO. © 1995 American Institute of Physics.