Figure 1

Experimental and theoretical integral cross sections (log-log units) for the reaction $\mathrm{S}({}^{1}D_2)+\mathrm{HD}$ as a function of collision energy for individual $\mathrm{DS}+\mathrm{H}$ and $\mathrm{HS}+\mathrm{D}$ channels and for the total reaction flux. Experimental ICSs (left vertical scale in arbitrary units, a.u.) for different crossed-beam conditions: down triangles $v_S=813\mathrm{m}{\mathrm{s}}^{-1}$ with speed ratio (see 31) $S=76$, $v_{\mathrm{HD}}=826\mathrm{m}{\mathrm{s}}^{-1}$ with $S>30$, ${\chi }_{\min }=12.5°$; squares $v_S=818\mathrm{m}{\mathrm{s}}^{-1}$ with $S=46$, $v_{\mathrm{HD}}=881\mathrm{m}{\mathrm{s}}^{-1}$ with $S>30$, ${\chi }_{\min }=22.5°$; up triangles $v_S=1736\mathrm{m}{\mathrm{s}}^{-1}$ with $S=27$, $v_{\mathrm{HD}}=881\mathrm{m}{\mathrm{s}}^{-1}$ with $S>30$, ${\chi }_{\min }=22.5°$. Inset: details of the $\mathrm{HS}+\mathrm{D}$ channel (linear scales): same symbols as above with another data set added: stars $v_S=776\mathrm{m}{\mathrm{s}}^{-1}$ with $S=43$, $v_{\mathrm{HD}}=826\mathrm{m}{\mathrm{s}}^{-1}$ with $S>30$, ${\chi }_{\min }=22.5°$. For clarity, the statistical uncertainties at the 95% confidence interval are only shown in the inset. Dashed lines: linear fits of the experimental total ICSs in the low- (1.63–5.63 meV) and high-energy (13.8–54.2 meV) domains. Theoretical ICSs (right vertical scale): filled circles (not shown for total ICSs); the solid curves refer to the theoretical ICSs convoluted over the experimental collision energy spread. Dash-dotted lines: linear fits of the theoretical total ICSs in the low- (0.86–3.45 meV) and high-energy (5.8–28.5 meV) domains. Supplementary theoretical total ICSs (right vertical scale) obtained with the PES of Varandas and coworkers [26]: filled diamonds.Reuse & Permissions

Figure 2

Partial-wave cross sections for selected $J$ values. (a) PES by Varandas and coworkers [26] $\mathrm{SD}+\mathrm{H}$ channel; (b) idem $\mathrm{SH}+\mathrm{D}$ channel; (c) PES by Ho et al. [20], $\mathrm{SD}+\mathrm{H}$ channel; and (d) idem $\mathrm{SH}+\mathrm{D}$ channel.Reuse & Permissions

Figure 3

Adiabatic effective potentials calculated for selected values of $J$, using the PES of Ho et al. [20]. Horizontal dash-dotted line: position of the shape resonance of the $J=19$ partial-wave at $E_T=7.3\mathrm{meV}$. Horizontal dashed line: position of the change in slope of the adiabatic ICSs, with inner and outer barriers for $J=17$ exhibiting equal heights of ca. 5.7 meV.Reuse & Permissions