Rotational analysis of the ground state of the Benzene·Ne van der Waals cluster cation by resolved high Rydberg spectroscopy

Series of resolved high n (40<n<110) Rydberg states of the benzene·Ne van der Waals cluster are measured by delayed field ionization after double resonance excitation with Fourier-transform limited UV laser pulses. A cross–correlation analysis yields the first rotationally resolved spectrum of an aromatic molecule noble gas cluster ion. Its analysis leads to accurate values for the adiabatic ionization energy (AIE=74497.512(30) cm−1) of the benzene·Ne cluster and the rotational constants of the cluster ion. The average van der Waals bonding length of the Ne atom from the (benzene)+-plane is 3.320(2) Å.