Relativistic four-component calculations of indirect nuclear spin-spin couplings with efficient evaluation of the exchange-correlation response kernel

摘要

In this work, we report on the development and implementation of a new scheme for efficientcalculation of indirect nuclear spin-spin couplings in the framework of four-component matrixDirac-Kohn-Sham approach termed matrix Dirac-Kohn-Sham restricted magnetic balance resolutionof identity for J and K, which takes advantage of the previous restricted magnetic balanceformalism and the density fitting approach for the rapid evaluation of density functional theoryexchange-correlation response kernels. The new approach is aimed to speedup the bottleneck in thesolution of the coupled perturbed equations: evaluation of the matrix elements of the kernel of theexchange-correlation potential. The performance of the new scheme has been tested on a representativeset of indirect nuclear spin-spin couplings. The obtained results have been compared with thecorresponding results of the reference method with traditional evaluation of the exchange-correlationkernel, i.e., without employing the fitted electron densities. Overall good agreement between bothmethods was observed, though the new approach tends to give values by about 4%-5% higher thanthe reference method. On the average, the solution of the coupled perturbed equations with thenew scheme is about 8.5 times faster compared to the reference method.