All-Electron Scalar Relativistic Basis Sets for Third-Row Transition Metal Atoms

Abstract

A family of segmented all-electron relativistically contracted (SARC) basis sets for the elements Hf-Hg is constructed for use in conjunction with the Douglas-Kroll-Hess (DKH) and zeroth-order regular approximation (ZORA) scalar relativistic Hamiltonians. The SARC basis sets are loosely contracted and thus offer computational advantages compared to generally contracted relativistic basis sets, while their sufficiently small size allows them to be used in place of effective core potentials (ECPs) for routine studies of molecules. Practical assessments of the SARC basis sets in DFT calculations of atomic (ionization energies) as well as molecular properties (geometries and bond dissociation energies for MHn complexes) confirm that the basis sets yield accurate and reliable results, providing a balanced description of core and valence electron densities. CCSD(T) calculations on a series of gold diatomic compounds also demonstrate the applicability of the basis sets to correlated methods. The SARC basis sets will be of most utility in calculating molecular properties for which the core electrons cannot be neglected, such as studies of electron paramagnetic resonance, Mössbauer and X-ray absorption spectra, and topological analysis of electron densities.

Characterizing the Solvated Structure of Photoexcited [Os(terpy)2]2+ with X-ray Transient Absorption Spectroscopy and DFT Calculations

“…The lowest-lying singlet ( 1 A 1 ) and triplet ( 3 MLCT) electronic states of [Os(terpy) 2 ] 2+ were fully optimized with the application of the gradient corrected BP86 [25,26] exchange-correlation functional in conjunction with the scalar relativistic (ZORA) TZVP atomic basis set [27] as implemented in the ORCA3.0 program package [28]. Solvation effects were taken into account by using the conductor-like screening model (COSMO) [29] with the selection of the dielectric constant of methanol (ε = 32.6).…”

Gaussian basis sets for molecular applications

“…[139][140][141] The SARC primitives are extrapolated based on CASSCF results, before contraction based on scalar relativistic CASSCF calculations. This procedure was carried out for the 5d transition metal elements, [142] the lanthanides, [143] and the actinides, [144] with a relativistic recontraction of the def2 basis sets performed for the elements of the first three rows of the periodic table to ensure consistency with the SARC bases. [142] DFT-based ZORA and DKH results using the SARC bases are in good agreement with experimental or high level ab initio results for ionization potentials, geometries, and bond dissociation energies.…”

Light-Induced Structural Change in Iridium Complexes Studied by Electron Spin Resonance

“…23 Ir atoms were described by segmented all-electron relativistically contracted (SARC) polarized triple-ξ-valence basis set (TZVPPP), and the lighter atoms were described by the SARC-TZVP basis set. 24 The calculations were performed using the ORCA computational package. 25 Figure 2 shows the LESR signals obtained for the complexes FIrpic and Ir(ppy) 3 in pure films and dispersed into the polymeric matrices polyfluorene (PFO), polystyrene (PS), and poly(methyl-methacrylate) (PMMA).…”