Quantitative electronic stopping power from localized basis set*

In charged particle irradiation, the electronic excitations are the prevailing phenomenon. The energy transfer from the projectile to the electrons of the target material is measured by the so-called electronic stopping power.
Today, it can be obtained from time-dependent density functional theory [1]. Most implementations rely on a plane-wave approach, however, at the expense of very cumbersome calculations.

In this work, we show that localized orbitals, especially Gaussian-type orbitals, can be an practical alternative [2].
They can yield electronic stopping powers in quantitative agreement with the plane-wave results, while retaining the computational burden relatively low. These positive results are only possible with the use of Gaussian basis sets specially designed for the stopping power evaluation. With this tool, we investigate the discrepancy between TDDFT calculations and experiment at large velocity, the role of core excitations in the total stopping power. We rule out the wide-spread centroid path approximation as soon as some core excitations are involved.

[1] A. Correa, Comput. Mat. Science 150, 291 (2018).
[2] I. Maliyov, J.-P. Crocombette, and F. Bruneval, Eur. Phys. J. B 91, 172 (2018).