Model description for single-electron transfer in slow-ion–${\mathrm{H}}_2$-molecule collisions: Studies for ${\mathrm{H}}^{+}$, ${\mathrm{He}}^{2+}$, and ${\mathrm{C}}^{4+}$ projectiles

We discuss a recently proposed model for describing single-electron transfer in slow- or intermediate-energy-ion–${\mathrm{H}}_2$-molecule collisions and present results for the examples of ${\mathrm{H}}^{+}$, ${\mathrm{He}}^{2+}$, and ${\mathrm{C}}^{4+}$-ion impact. The dynamics of the two active electrons is given by a one-electron potential model, within the framework of the semiclassical close-coupling description, in conjunction with conservation of the norm of the total two-electron wave function. Considerable numerical simplifications occur when the length of the molecular axis is set to zero. It is argued that this model description of ion-molecule collisions is both efficient and remarkably accurate.