Author:

Keywords:

Science & Technology, Physical Sciences, Chemistry, Physical, Physics, Atomic, Molecular & Chemical, Chemistry, Physics, GAS-PHASE THERMOCHEMISTRY, HIGHLY CORRELATED SYSTEMS, S/D EXCITATION-ENERGIES, BASIS-SET CONVERGENCE, GAUSSIAN-BASIS SETS, FOCK HYBRID METHODS, GUIDED ION-BEAM, ELECTRONIC-ENERGY, BOND-ENERGIES, PERIODIC TRENDS, Electrons, Models, Molecular, Quantum Theory, Sensitivity and Specificity, Thermodynamics, Transition Elements, 02 Physical Sciences, 03 Chemical Sciences, 09 Engineering, Chemical Physics, 34 Chemical sciences, 40 Engineering, 51 Physical sciences

Abstract:

This paper describes the development of the B3LYP localized orbital correction model which improves the accuracy of the B3LYP thermochemical predictions for compounds containing transition metals. The development of this model employs a large data set containing 36 experimental atomic energies and 71 bond dissociation energies. B3LYP calculations were carried out on these systems with different basis sets. Based on an electronic structure analysis and physical arguments, we built a set of 10 parameters to correct atomic data and a set of 21 parameters to correct bond dissociation energies. Using the results from our biggest basis set, the model was shown to reduce the mean absolute deviation from 7.7 to 0.4 kcalmol for the atomic data and from 5.3 to 1.7 kcalmol for the bond dissociation energies. The model was also tested using a second basis set and was shown to give relatively accurate results too. The model was also able to predict an outlier in the experimental data that was further investigated with high level coupled-cluster calculations.