Infrared Spectrum and Structure of the Adamantane Cation: Direct Evidence for Jahn–Teller Distortion

The fundamentals: the IR spectrum of the adamantane cation, C(10)H(16)(+), has been derived by resonant IR photodissociation of weakly bound C(10)H(16)(+)⋅L(n) clusters. The analysis of the IR spectrum provides the first spectroscopic characterization of this fundamental cycloalkane carbocation in the gas phase and direct evidence for the Jahn-Teller distortion in the (2)A(1) ground electronic state.