A pseudopotential-based composite method: The relativistic pseudopotential correlation consistent composite approach for molecules containing 4d transition metals (Y–Cd)

Abstract

The correlation consistent composite approach (ccCA) has proven to be an effective first-principles-based composite approach for main group and first-row transition metal species. By combining relativistic pseudopotentials and ccCA, accurate energetic and thermodynamic data for heavier elements, including transition metals, is obtainable. Relativistic pseudopotential ccCA (rp-ccCA) was formulated and tested on 25 molecules from the G3∕05 set that contain 4p elements (Ga-Kr). A 32.5% time savings was obtained using rp-ccCA, relative to ccCA employing all-electron basis sets. When implementing rp-ccCA to compute dissociation energies and enthalpies of formation for molecules from the 4p block, rp-ccCA results in a mean absolute deviation of 0.89 kcal mol(-1) from experimental data. rp-ccCA was also applied to a set of 30 4d transition metal-containing molecules, ranging from diatomics to Mo(CO)(6), and enthalpies of formation for these species were obtained with a mean absolute deviation of 2.89 kcal mol(-1) in comparison to experimental data. Based on quality of the experimentally available enthalpies of formation, where the average value of reported experimental error bars is 3.43 kcal mol(-1), rp-ccCA is within transition metal chemical accuracy for the 4d molecule set. rp-ccCA is a pseudopotential-based composite method for transition metals and is shown to yield accurate thermodynamic results for molecules containing heavy elements Ga-Kr and Y-Cd.

Prediction of CB[8] host–guest binding free energies in SAMPL6 using the double-decoupling method

“…However, partial charges for the bonus guest molecule G13 needed special consideration as the guest contained a platinum (Pt II) atom which required the use of effective core potentials. In the case of G13, triple-zeta quality correlation consistent basis sets (cc-pVTZ) with the respective relativistic pseudopotential for Pt (cc-pVTZ-PP) [39] were used, based on an effective pseudopotential-based composite method, rp-ccCA [67]. Geometry optimizations were performed using B3LYP and ESP charges were obtained based on MP2 densities, using an atomic radius of 2.0 Å for Pt.…”

Pseudopotential-Based Correlation Consistent Composite Approach (rp-ccCA) for First- and Second-Row Transition Metal Thermochemistry

“…63,64 In the initial rp-ccCA study, Laury and coworkers obtained accurate ΔH f 's (within 1.0 kcal/mol from reliable, well-established experiment for main group) for 25 4p-containing molecules and observed a computational time savings of over 30% in comparison to all-electron composite methods. 64 Laury and co-workers then applied rp-ccCA to a set of 30 4d transition metal compounds, achieving a mean absolute deviation (MAD) of 2.89 kcal/mol from experimental ΔH f 's.…”

Prediction of pKas of Late Transition‐Metal Hydrides via a QM/QM Approach

“…For Ni species, correlation consistent basis sets with the one‐particle Douglas–Kroll–Hess Hamiltonian for scalar relativistic effects were applied (e.g., aug‐cc‐pVTZ‐DK) for all atoms . For Pd and Pt species, the small‐core relativistic pseudopotential basis sets (e.g., aug‐cc‐pVTZ‐PP) were used for Pd and Pt, while the all‐electron basis sets (e.g., aug‐cc‐pVTZ) were used for main group atoms because the pseudopotentials are incompatible with the DKH Hamiltonian and are constructed to account for relativistic effects of the heavy atom . In the following sections, the terms DK for Ni and PP for Pd and Pt are dropped for clarity from the selected basis set notations.…”