High resolution electronic spectroscopy of Ne⋅OH

The high resolution electronic spectrum of Ne⋅OH has been recorded in a supersonic free jet expansion using the laser-induced fluorescence technique. From an analysis of the spectrum which yields rotational constants, we are able to obtain Ne⋅OH bond lengths in several vibrational (hindered rotor) levels of the excited state and the vibrationless level of the ground state. We also measure the Fermi contact constant in the à state which is, unlike Ar⋅OH, insignificantly perturbed from the value in the OH monomer. However, we now measure a parity doubling of the X̃ state rotational levels which is tenfold larger than the upper limit we established for such an interaction in Ar⋅OH. We interpret these latter measurements to imply weaker and more isotropic bonding in Ne⋅OH compared to Ar⋅OH in both electronic states.