Estimation of a priori errors in ab initio calculations of thermochemical values for the example of the dissociation energies of the ZnO and ZnS molecules

The total energies of ZnO(¹Σ), ZnO(³Π), ZnO^?(²Σ), ZnO⁺(²Σ), ZnS(¹Σ), ZnS(³Π), ZnS^?(²Σ), and ZnS⁺(²Σ) were calculated ab initio by the CCSD(T) method with the use of atomic basis sets including 80, 84, and 93 functions for O, S, and Zn, respectively. Similar calculations were performed for the Zn atom Zn(¹ S), Zn(³ P), Zn⁺(² S), Zn²⁺(¹ S)] and several oxygen and sulfur states O(³ P), O^?(² S), O(¹ D), O₂(³Σ), O ₂ ^? (²Π), O₂(¹Δ), S(³ P), S^?(² S), S(¹ D), S₂(³Σ), S ₂ ^? (²Π), and S₂(¹Δ)]. The ideology of engagement groups suggested by us is considered. According to this approach, data treatment can be performed on the assumption that the errors in all the 24 results obey the normal distribution law. As a result, we obtained D _e(ZnO) = 1.70 ± 0.21 and D _e(ZnS) = 1.57 ± 0.25 eV (at a 95% confidence level).