Comparative study of elastic electron collisions on the isoelectronic SiN 2 , SiCO , and CSiO radicals

We report a theoretical study of elastic electron collisions on three isoelectronic free radicals, namely, $\mathrm{SiNN}$, $\mathrm{SiCO}$, and $\mathrm{CSiO}$. More specifically, differential, integral, and momentum-transfer cross sections are calculated and reported in the $(1\char21{}100)\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ energy range. Calculations are performed at the static-exchange-polarization-absorption level of approximation. A combination of the iterative Schwinger variational method and the distorted-wave approximation is used to solve the scattering equations. Our study reveals that the calculated cross sections for the ${e}^{\ensuremath{-}}\text{\ensuremath{-}}\mathrm{SiNN}$ and ${e}^{\ensuremath{-}}\text{\ensuremath{-}}\mathrm{SiCO}$ collisions are very similar even at incident energies as low as $3\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$. Strong isomeric effects are also observed in the calculated cross sections for ${e}^{\ensuremath{-}}\text{\ensuremath{-}}\mathrm{CSiO}$ and ${e}^{\ensuremath{-}}\text{\ensuremath{-}}\mathrm{SiCO}$ collisions, particularly at incident energies below $20\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$. It is believed that the position of the silicon atom being at the center or extremity of the molecules may exert important influence on the calculated cross sections.