Ab initio potential energy surfaces for the 1A′ and 3A′ states of the MgH(X2Σ+) + H(2S) system

The two potential energy surfaces (PESs) associated to the (1)A' and (3)A' states correlating to the interacting MgH(X-2 Sigma(+)) + H(S-2) system were determined from ab initio calculations. They were obtained using the aug-cc-pVQZ basis set for the H atom and the cc-pV5Z basis set for the Mg atom and multireference internally contracted configuration-interaction (MRCI) method including Davidson correction. The MgH distance was kept fixed at its experimental equilibrium distance in the X-2 Sigma ground state. The ab initio calculated interaction energies of the two PESs were. fitted analytically on the basis of Legendre polynomials for future collisional rotational excitation study. The (1)A' and (3)A' adiabats both present very deep well corresponding to the MgH2 complex. (C) 2009 Elsevier B. V. All rights reserved.