Electronic structure and rovibrational properties of ZnOH in the (X)over-tilde 2A′electronic state: A computational molecular spectroscopy study

The three-dimensional ground-state potential energy surface of ZnOH has been calculated ab initio at the MR-SDCI+Q_DK3/[QZP ANO-RCC (Zn, O, H)] level of theory and used as basis for a study of the rovibrational properties carried out by means of the program MORBID (Morse Oscillator Rigid Bender Internal Dynamics). The electronic ground state is (2)A' (correlating with (2)Sigma(+) at the linear configuration). The equilibrium structure has r(e)(Zn-O) = 1.8028 angstrom, r(e)(O-H) = 0.9606 angstrom, and angle(e)(Zn-O-H) = 114.9 degrees. The Zn-O bond is essentially ionic, with appreciable covalency. The bonding character is compared with those of FeOH (quasi-linear) and CsOH (linear). The rovibrationally averaged structural parameters, determined as expectation values over MORBID wavefunctions, are < r(Zn-O)>(0) = 1.8078 angstrom, < r(O-H)(0) = 0.9778 angstrom, and (0) = 117 degrees. The Yamada-Winnewisser quasi-linearity parameter is found to be gamma(0) = 0.84, which is close to 1.0 as expected for a bent molecule. Since no experimental rovibrational spectrum has been reported thus far, this spectrum has been simulated from the ab initio potential energy and dipole moment surfaces. The amphoteric character of ZnOH is also discussed. (C) 2014 AIP Publishing LLC.