Gauge-origin dependence in electronic g-tensor calculations

Glasbrenner, Michael; Vogler, Sigurd and Ochsenfeld, Christian (2018): Gauge-origin dependence in electronic g-tensor calculations. In: Journal of Chemical Physics, Vol. 148, No. 21, 214101

Abstract

We present a benchmark study on the gauge-origin dependence of the electronic g-tensor using data from unrestricted density functional theory calculations with the spin-orbit mean field ansatz. Our data suggest in accordance with previous studies that g-tensor calculations employing a common gauge-origin are sufficiently accurate for small molecules;however, for extended molecules, the introduced errors can become relevant and significantly exceed the basis set error. Using calculations with the spin-orbit mean field ansatz and gauge-including atomic orbitals as a reference, we furthermore show that the accuracy and reliability of common gauge-origin approaches in larger molecules depends strongly on the locality of the spin density distribution. We propose a new pragmatic ansatz for choosing the gauge-origin which takes the spin density distribution into account and gives reasonably accurate values for molecules with a single localized spin center. For more general cases like molecules with several spatially distant spin centers, common gauge-origin approaches are shown to be insufficient for consistently achieving high accuracy. Therefore the computation of g-tensors using distributed gauge-origin methods like gauge-including atomic orbitals is considered as the ideal approach and is recommended for larger molecular systems. Published by AIP Publishing.

• Item Type: Journal article
• Research Centers: Center for Integrated Protein Science Munich (CIPSM)
• Subjects: 500 Science > 540 Chemistry
• ISSN: 0021-9606
• Language: English