Ab initio electronic and rovibrational structure of MgH22+

The electronic structure of the ground state of MgH22+ has been investigated using relativistically-corrected CCSD(T) in conjunction with ANO-RCC (Mg) and aug-cc-pVQZ (H) basis sets. The MgH22+ molecular potential energy surface possessed minima corresponding to both (1)A(1) and (1)Sigma(+)(g) equilibrium structures (with a (1)Sigma(+) transition state). The (1)A(1) structure possessed R-e and 0(e) values of 2.0297 angstrom and of 22.09 degrees, respectively. The higher-energy (1)Sigma(+)(g) structure exhibited an R-e value of 2.1658 angstrom. Property surfaces were constructed to calculate rovibratiognal energies and spectral line intensities for the ground states of ((1)A(1))MgH22+, ((1)A')MgH22+ and ((1)A(1))MgH22+. For the vibration ground state of ((1)A(1))MgH22+, the vibration-averaged R-e and 0(e) values were calculated to be 2.0209 angstrom and 22.53 degrees, respectively. The A, B and C rotational constants were calculated to be 58.0, 2.21 and 2.11 cm(-1), respectively. (c) 2008 Elsevier B.V. All rights reserved.