A method to obtain meV-collision-energy resolution in scattering studies: application to the H+D2 → HD(ν′=0, j′)+D(θrel<80°) reaction at Erel=1.275±0.011 eV Original Research Article

Previous work has shown that a one-to-one correspondence between the speed and scattering angle of state-selected AB products of the gas-phase reaction sequence AX+hν → A+X, A+BC → AB+C can be exploited to measure state-to-state differential cross-sections without resorting to molecular beams. Here we demonstrate a modification to this photoinitiated technique that enables for the observation of the forward- and backward-scattered products of a reaction with improved collision energy resolution. This modification is demonstrated by its application to the measurement of the j′ dependence of the yield of forward-scattered HD product in the reaction H+D2 → HD(ν′=0, j′)+D at 1.275±0.011 eV. The data obtained are consistent with quantum scattering calculations that do not include the geometric phase.