Spin‐orbit ZORA and four‐component Dirac–Coulomb estimation of relativistic corrections to isotropic nuclear shieldings and chemical shifts of noble gas dimers

Abstract

Hartree-Fock and density functional theory with the hybrid B3LYP and general gradient KT2 exchange-correlation functionals were used for nonrelativistic and relativistic nuclear magnetic shielding calculations of helium, neon, argon, krypton, and xenon dimers and free atoms. Relativistic corrections were calculated with the scalar and spin-orbit zeroth-order regular approximation Hamiltonian in combination with the large Slater-type basis set QZ4P as well as with the four-component Dirac-Coulomb Hamiltonian using Dyall's acv4z basis sets. The relativistic corrections to the nuclear magnetic shieldings and chemical shifts are combined with nonrelativistic coupled cluster singles and doubles with noniterative triple excitations [CCSD(T)] calculations using the very large polarization-consistent basis sets aug-pcSseg-4 for He, Ne and Ar, aug-pcSseg-3 for Kr, and the AQZP basis set for Xe. For the dimers also, zero-point vibrational (ZPV) corrections are obtained at the CCSD(T) level with the same basis sets were added. Best estimates of the dimer chemical shifts are generated from these nuclear magnetic shieldings and the relative importance of electron correlation, ZPV, and relativistic corrections for the shieldings and chemical shifts is analyzed.

Relativistic DFT Calculations of Hyperfine Coupling Constants in 5d Hexafluorido Complexes: [ReF6]2− and [IrF6]2−

“…Evidently, the isotropic hyperfine coupling constant changed only slightly but in a consistent manner when the basis set was increased by using the DKS method and Dyall's basis sets, whereas we observed the same irregular, no‐monotonic behaviour of the ZORA basis sets, as seen previously, for nuclear magnetic shielding 31, 32. It was shown there, that the increasing cardinal number and the increasing amount of polarization functions have opposite effects, which lead to an oscillating and not yet converging behaviour.…”

“…For example, previous studies showed that, in ZORA calculations of nuclear magnetic shielding constants, it was important to use the large QZ4P basis sets 31, 32. Therefore, we also studied the basis set dependence of both the ZORA and DKS results for the hyperfine coupling constants in both ions.…”

“…[30] For example, previous studies showed that, in ZORA calculations of nuclear magnetic shieldingc onstants,i tw as important to use the large QZ4P basis sets. [31,32] Therefore, we also studied the basis set dependence of both the ZORA and DKS resultsf or the hyperfine coupling constants in both ions. Ta ble 1s hows the LR ZORA and EV ZORA results of the isotropic hyperfine coupling constant of Re IV and Ir IV complexes, respectively,w hich were obtained with the special ZORA STO basis sets DZ, TZ2P,a nd QZ4P,a s well as DKS 4-component results, whichw ere obtainedw ith Dyalls vdz, vtz, and vqz GTO basis sets.…”

Local aromaticity mapping in the vicinity of planar and nonplanar molecules

“…The 3 He NMR spectral range is moderate. Very small chemical shift is observed for helium in He 2 and benzene‐He dimers . In the latter complex, the spherical helium atom is located 3.6 Å from the middle of benzene ring and exhibits only relatively small change of its nuclear shielding with respect to free atom .…”

Prediction of 195Pt NMR of photoactivable diazido‐ and azine‐Pt(IV) anticancer agents by DFT computational protocols

“…It is well established that relativistic and spin orbit effects strongly contribute to computed σ iso 195 Pt magnetic shielding tensor elements of Pt(II) and Pt(IV) coordination compounds, but this contribution is effectively canceled in the computed δ 195 Pt chemical shifts with respect to the reference standards, because the relativistic corrections are expected to be similar in the complexes and the reference standards. Very recently, Jankowska et al studying systematically the importance of relativistic effects for the noble gas nuclear shielding and the He 2 ‐Xe 2 noble gas dimers chemical shifts showed that for the chemical shifts of the noble gas dimers, the relativistic corrections almost cancel.…”