Measurement of the spin-exchange and chemical ionization rate constants in collisions of polarized metastable 2$^3$S$_1$ helium atoms with 3$^2$S$_{1/2}$ sodium atoms

Experimental data on the spin-exchange rate constants for the He(2$^3$S$_1$)–Na(3$^2$S$_{1/2}$) system are reported for the first time. Measurements show that the spin-exchange rate constant is $C_{se}$ = (23 $\pm$ 11) $\times$ 10$^{-10}$ cm$^3$ s$^{-1}$ and the chemical ionization rate constant is $C_{ci}$ = (29 $\pm$ 14) $\times$ 10$^{-10}$ cm$^3$ s$^{-1}$ at a temperature of 420 K. The results are compared with the data calculated from the rate constants.