“…Several groups of investigators have reported the formation by ion-molecule reactions in a mass spectrometer of molecular ions containing rare gas atoms (1)(2)(3)(4)(5)(6)(7)(8). Such ions have included ZH+ (1)(2)(3)(4) and small amounts (less than 1 percent of the total ionization) of ZCmHn+ (m = 1, 2; n = 0 to 4) (1-3, 5,6), ZY+ (Y = Cl, Br, I, 0) (5), ZC2N2+ (7), Z2+ (1,2,8,9), ZN2+ (9), and ZCO+ (9), where Z is a rare gas atom, usually xenon.…”