Theoretical studies of the (X)over-tilde (2)Pi and (A)over-tilde (2)Sigma(+) states of the He center dot OH and Ne center dot OH complexes

Potential energy surfaces for the (X) over tilde (2)Pi and (A) over tilde ( 2)Sigma(+) states of the He . OH and Ne . OH complexes have been developed, using the restricted open-shell coupled cluster [RCCSD(T)] method. These p otentials have been used to calculate rotation-vibration energies for both electronic states of these complexes and their deuterated analogs. Good agr eement with the available experimental vibrational energies and rotational constants is obtained. In spite of being relatively weakly bound, the vibra tional eigenstates for both electronic states of these species display sign ificant deviations from the simple zero-order free-rotor/anharmonic oscilla tor limit, leading to potentially rich spectra. (C) 2000 American Institute of Physics. [S0021-9606(00)30138-6].