Calculating the fraction of metastable helium atoms which are formed in the $He^{1+} + Na \to He+Na^{1+}$ reaction

The portion of metastable particles which are formed with neutralization of $He^{1+}(^1S)$ ions in Na vapors in a region of collision rates of $v$ from 0.3 to 10 atomic units (at. un.) is calculated. The role in the formation of the fraction of metastable helium atoms of the process of electron capture into highly excited states with subsequent transitions to the metastable levels is explained. A comparison with the available experimental data is performed.