Atomic C₆ dispersion coefficients: a four-component relativistic Kohn–Sham study

Abstract

We present C ₆ homo- and heteroatomic dispersion coefficients for all closed-shell atoms of the periodic table based on dipole–dipole polarizabilities at imaginary frequencies calculated using our recent extension of the complex polarization propagator approach to the four-component relativistic Kohn–Sham approach. Lack of proper reference data bars definite conclusions as to which density functional shows the overall best performance, and we therefore call for state-of-the-art wave function-based correlated calculations of dispersion coefficients. Scalar relativistic effects are significant already for elements as light as zinc, whereas spin–orbit effects must be taken into account only for very heavy elements.

Keywords:

• van der Waals interaction
• C6 dispersion coefficient
• relativistic effects
• density functional theory

Acknowledgements

D.S. was supported by a PhD grant from the Ministère de l'Enseignement Supérieur et de la Recherche (France). P.N. acknowledges financial support from the Swedish Research Council (Grant No. 621-2010-5014). T.S. acknowledges valuable discussions with Stephan Ehrlich and Stefan Grimme. We dedicate this paper to our mate Peter Taylor for whom no number is too small.