STATE-TO-STATE DIFFERENTIAL CROSS-SECTIONS FOR THE REACTION CL((2)P(32))+CH4(NU-3=1,J=1)-]HCL(NU'=1,J')+CH3/

A mixture of methane and chlorine molecules in a helium carrier is exp anded into a vacuum chamber using a pulsed valve. Polarized laser phot olysis of Cl2 at 355 nm is used to produce Cl(P-2(3/2)) With a sharply peaked speed distribution and a known angular distribution. Methane m olecules are excited in the asymmetric stretch mode by infrared absorp tion to the nu3=1, J=1 state. Following a 100 ns time delay to allow f or reaction, HCl(v'= 1, J') product molecules are probed by (2+1) reso nance-enhanced multiphoton ionization. The resulting photoions are det ected with both mass and velocity resolution using a linear time-of-fl ight mass spectrometer. Application of the methods described by Shafer et al., allows determination of the differential cross section for th e specific rovibrational state ionized at a center-of-mass collision e nergy of 0.159 eV. The time-of-flight data show a change in the produc t angular distribution with J' and thus demonstrate the importance of measuring quantum-state-resolved differential cross sections for eluci dating the dynamics of this reaction system.