A charge transfer complex CH +3—Ar in the gas phase

Abstract

The thermochemical data Δ H 0 n−1, n and Δ S 0 n−1, n for clustering reactions CH + 3(Ar) n−1 + Ar⇌CH + 3(Ar) n were determined with a pulsed electron beam high-pressure mass spectrometer. It was found that (1) the bond energy of CH + 3(Ar) n with n = 1 (−Δ H 0 0,1 = 11.3 kcal/mol) is much higher than that with n = 2 (−ΔH 0 1,2 = 2.26 kcal/mol); (2) −Δ H 0 1,2 is slightly greater than −Δ H 0 2,3 (1.97 kcal/mol), and (3) the −Δ H 0 n−1, n values with n = 3−8 are almost n-independent. The structures of CH + 3(Ar) n with n = 1−3 were determined by ab initio MO calculations. The theoretical calculations predict some participation of covalent bond (charge transfer) in CH + 3(Ar) n with n = 1 and 2. The nature of bonding in the complex with n ⩾ 3 is almost entirely electrostatic.