Regensburg 2019 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 8: Frontiers of Electronic-Structure Theory: Focus on the Interface Challenge I (joint session O/CPP/DS/TT)
TT 8.7: Vortrag
Montag, 1. April 2019, 12:15–12:30, H9
Quantum-mechanical relation between atomic dipole polarizability and van der Waals radius — •Dmitry Fedorov, Mainak Sadhukhan, Martin Stöhr, and Alexandre Tkatchenko — University of Luxembourg, Luxembourg, Luxembourg
The atomic dipole polarizability α and the van der Waals (vdW) radius RvdW are two key quantities to describe the ubiquitous vdW forces important for the structure and dynamics of molecules and materials [1]. The commonly assumed relation between them, RvdW ∝ α1/3, is based on a classical picture of hard-sphere atoms. Employing the quantum Drude oscillator model [2], we reveal [3] the quantum-mechanical relation RvdW = const. ×α1/7 which is markedly different from its classical counterpart. Based on the accessible accurate reference data for α and RvdW, we demonstrate that the obtained formula can be used as a unified definition of the vdW radius solely in terms of the atomic polarizability for all chemical elements. Moreover, for vdW-bonded heteronuclear dimers consisting of atoms A and B, the simple combination rule α = (αA + αB)/2 provides a remarkably accurate way to calculate their equilibrium interatomic distance. These findings unveil a fundamental relationship between the geometric and electronic properties of atoms. From a practical point of view, they allow us to reduce the empiricism and improve the efficiency of computational models for vdW interactions.
[1] Hermann et al., Chem. Rev. 117, 4714 (2017)
[2] Jones et al., Phys. Rev. B 87, 144103 (2013)
[3] Fedorov et al., Phys. Rev. Lett. 121, 183401 (2018)