Commonly used exchange-correlations functionals are known to produce inaccurate electric field gradient (EFG) values at the nuclei of transition metals and heavy atoms in molecular calculations. This makes density functional theory (DFT) essentially inapplicable for the determination of nuclear quadrupole moments (NQM) from absolute EFG estimates. However, in a recently proposed indirect approach, the NQM is determined from the changes in the EFG along a series of molecules. We investigate this indirect approach within four-component relativistic DFT, showing that, at least in a series of chemically strictly related molecules, EFG variations can be com- puted quite accurately. This leads to surprisingly stable and reliable estimates of the NQM, even in notoriously ‘difficult’ cases such as 197Au.
An indirect approach to the determination of the nuclear quadrupole moment by 4-component relativistic DFT in molecular calculations
BELPASSI, LEONARDO;TARANTELLI, Francesco;SGAMELLOTTI, Antonio;
2007
Abstract
Commonly used exchange-correlations functionals are known to produce inaccurate electric field gradient (EFG) values at the nuclei of transition metals and heavy atoms in molecular calculations. This makes density functional theory (DFT) essentially inapplicable for the determination of nuclear quadrupole moments (NQM) from absolute EFG estimates. However, in a recently proposed indirect approach, the NQM is determined from the changes in the EFG along a series of molecules. We investigate this indirect approach within four-component relativistic DFT, showing that, at least in a series of chemically strictly related molecules, EFG variations can be com- puted quite accurately. This leads to surprisingly stable and reliable estimates of the NQM, even in notoriously ‘difficult’ cases such as 197Au.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
