Fig. 1: Experimental images and vibrational state-specific angular distributions.
From: Revealing umbrella bending as a reporter mode in the D+CH4 reaction
a Experimental time-sliced velocity map image of CH3(v’ = 0) products at a collision energy of 0.66 eV. The color scale represents the ion counts of CH3+. b The experimental time-sliced velocity map image of CH3(v’ = 1) products at a collision energy of 0.66 eV. The Newton diagram for the D + CH4 reactive scattering is depicted by red lines. The “CH4” and “D” denote the directions of the two reactant beams. “F” and “B” denote the forward and backward scattering directions corresponding to the incident CH4 beam in the center-of-mass (COM) frame. “CM” denotes the center of mass for reactive scattering. d, e The same as (a and b), except at a collision energy of 0.99 eV. g, h The same as (a and b), except at a collision energy of 1.55 eV. c, f and (i)The experimental (Exp.) and calculated (Theo.) differential cross sections (DCSs) at collision energies of 0.66, 0.99, and 1.55 eV, respectively, in units of Å2 sr−1, in which sr stands for steradian. The experimental DCSs for CH3(v’ = 0) and CH3(v’ = 1) products are plotted in dark blue and bright orange, while the calculated DCSs for CH3(v’ = 0) and CH3(v’ = 1) products are plotted in dark cyan and strong red. To better present the different angular distributions of the v’ = 0 and 1 product states at each collision energy, the DCS of the v’ = 1 product is scaled to a similar amplitude as the v’ = 0 product. 0 and 180° represent the forward and backward scattering directions, respectively. The counting events were about 500,000 laser shots for the CH3(v’ = 0) reaction channel, while the counting events were about 2,000,000 laser shots for the CH3(v’ = 1) reaction channel. The error bars for experimental DCSs are estimated to be about 10%, which mainly comes from the uncertainty of experimental measurement and the fitting process. Source data are provided as a Source Data file.
