Structure and dynamics of the negative-ion resonance in H2, D2 , and HD at 10 eV

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The angular distribution of the anions formed in the dissociative electron attachment (DEA) to ${\mathrm{H}}_{2}, {\mathrm{D}}_{2}$, and HD is studied for the 10-eV resonance using the velocity slice imaging technique. The angular distributions of ${\mathrm{H}}^{\ensuremath{-}}$ and ${\mathrm{D}}^{\ensuremath{-}}$ from HD are found to be identical and very similar to that of ${\mathrm{H}}^{\ensuremath{-}}$ (${\mathrm{D}}^{\ensuremath{-}}$) from ${\mathrm{H}}_{2}$ (${\mathrm{D}}_{2}$) indicating that the distinct dissociation limits for ${\mathrm{H}}^{\ensuremath{-}}$ and ${\mathrm{D}}^{\ensuremath{-}}$ channels and the small but finite dipole moment of HD do not affect the DEA process. The angular distributions suggest that the main contribution for this resonance is from the capture of $s$ and $d$ partial waves of the attaching electron confirming the resonance to be a ${}^{2}{{\mathrm{\ensuremath{\Sigma}}}_{g}}^{+}$ state. The relative amplitudes of the two partial waves as a function of electron energy also indicate the contribution from a higher-lying ${}^{2}{{\mathrm{\ensuremath{\Sigma}}}_{g}}^{+}$ state through possible predissociation at higher electron energies.