FORMATION OF AR+(4P) BY HE(2 S-3)+AR+(P-2(3/2)) EXCITATION TRANSFER AND HE++AR(P-3(2)) CHARGE-TRANSFER IN THE HELIUM FLOWING AFTERGLOW

ArII lines have been observed by addition of Ar into the He flowing afterglow. The effect of ion collection in the He afterglow and the energetics lead us to conclude that the He (2 3S) + Ar+ (3p5 P-2(3/2)0) excitation transfer gives the ten Ar+ (4p P-4(5/2,3/2,1/2(0), 4p 4D7/2,5/2,3/2,1/2(0), 4p 2D5/2,3/2(0), 4p P-2(1/2)0) levels in the 19.22-19.80 eV range, while the He+ +Ar(4s P-3(2)0) charge transfer populates the three Ar+ (4p P-2(3/2(0), 4p S-4(3/2,)0 4p S-2(1/2)0) levels in the 19.87-19.97 eV range. The relative rate constants for excitation of individual Ar+ (4p) ions have been measured. The favored exit channel is the 4p P-4(3/2)0 level in the former reaction, and the 4p P-2(3/2)0 level in the latter reaction. Since these channels are 0.5-0.6 eV below the entrance channels, attractive entrance potentials are probably important for both reactions.