Recent Advances in Electronic Structure Theory and Their Influence on the Accuracy of Ab initio Potential Energy Surfaces

Abstract

Recent advances in electronic structure theory and the availability of high speed vector processors have substantially increased the accuracy of ab initio potential energy surfaces. The recently developed atomic natural orbital approach for basis set contraction has reduced both the basis set incompleteness and superposition errors in molecular calculations. Furthermore, full CI calculations can often be used to calibrate a CASSCF/MRCI approach that quantitatively accounts for the valence correlation energy. These computational advances also provide a vehicle for systematically improving the calculations and for estimating the residual error in the calculations. Calculations on selected diatomic and triatomic systems will be used to illustrate the accuracy that currently can be achieved for molecular systems. In particular, the F+H2 → HF+H potential energy hypersurface is used to illustrate the impact of these computational advances on the calculation of potential energy surfaces.KeywordsBarrier HeightSpectroscopic ConstantElectronic Structure TheoryAtomic Natural OrbitalCanonical Variational Transition State TheoryThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.