Journal of Physical Chemistry A, Vol.115, No.17, 4436-4447, 2011
First-Principles Calculations of the Electronic and Geometrical Structures of Neutral [Sc,O,H] Molecules and the Monocations, ScOH0,+ and HScO0,+
Using multireference configuration interaction and coupled-cluster methodologies, with quadruple-c basis sets, we explored the potential energy surfaces of the ground and excited states of the neutral and cationic triatomics [Sc,O,H](0,+). In its ground state, the neutral species is trapped into either a linear ScOH or a bent HScO conformation; these two minima are approximately equal in energy and separated by a barrier of 40 kcal/mol. The linear ScOH structure is preferred by the excited states of the neutral species and by all of the electronic states of the charged molecular systems that we studied in this work. Both ScOH and ScOH+ present ionic characters, Sc+OH- and Sc2+OH-, similar to those found for the isovalent ScF0,+ species. The HScO0,+ structures are obtained by covalent or dative interaction of hydrogen and ScO0,+. For most of the minima located in this work, we calculated geometries, vibrational frequencies, binding energies, excitation energies, and dipole moments. Our numerical results agree well with existing experimental data.