Scattering-angle resolved product rotational alignment for the reaction of Cl with vibrationally excited methane

Abstract

We have applied the experimental technique of core extraction [W. R. Simpson et al., J. Chem. Phys. 103, 7299 (1995)] combined with resonance-enhanced multiphoton ionization (REMPI) with a polarized laser beam to probe the angular-momentum alignment of the HCl product of the reaction of Cl with vibrationally excited CH4(ν3=1). The core extraction method permits us to distinguish products scattered in different directions in the center-of-mass frame, and thus we are able to determine the rotational alignment for various product scattering angles for individual HCl(v,J) quantum states (a state-resolved three-vector correlation). For the forward-scattered HCl(v=1, J=1) we observe a large positive rotational alignment. This positive velocity-angular-momentum correlation is interpreted to be the result of the angular momentum of the HCl product being directed in the plane perpendicular to the line-of-centers force in a simple hard-sphere scattering model.