Isotope effects in inelastic 1.5-keVHe+-(H2,D2) collisions

Linear-and circular-polarization measurements have been made for the $3{}_{}{}^3{}_{}{}^{}P\to 2{}_{}{}^3{}_{}{}^{}S$ transitions in helium resulting from the collision processes, ${\mathrm{He}}^{+}+\frac{{\mathrm{H}}_2}{{\mathrm{D}}_2}\to \mathrm{He}\left(3\mathrm{} {}_{}{}^3{}_{}{}^{}P\right)+\frac{{{\mathrm{H}}_2}^{+}}{{{\mathrm{D}}_2}^{+}}$. This was carried out at an incident-ion lab energy of 1.5 keV and for laboratory scattering angles ranging from 0.50 to 2.33 deg. The behavior of linear polarization for ${\mathrm{H}}_2$ and ${\mathrm{D}}_2$ targets as a function of scattering angle was found to be different, contrary to what one would expect from simple models that depend only upon the electronic structure of the system. Some correlation of the circular polarization between the two isotopes was found.