Time-dependent density functional theory calculations of electronic friction in non-homogeneous media

The excitation of low-energy electron–hole pairs is one of the most relevant processes in the gas–surface interaction. An efficient tool to account for these excitations in simulations of atomic and molecular dynamics at surfaces is the so-called local density friction approximation (LDFA). The LDFA is based on a strong approximation that simplifies the dynamics of the electronic system: a local friction coefficient is defined using the value of the electronic density for the unperturbed system at each point of the dynamics. In this work, we apply real-time time-dependent density functional theory to the problem of the electronic friction of a negative point charge colliding with spherical jellium metal clusters. Our non-adiabatic, parameter-free results provide a benchmark for the widely used LDFA approximation and allow the discussion of various processes relevant to the electronic response of the system in the presence of the projectile.
This work has been supported in part by the Basque Departamento de Educación, Universidades e Investigación, the University of the Basque Country UPV/EHU (Grant No. IT1246-19), the Spanish Ministerio de Ciencia e Innovación (MICIN) Grants No. PID2019-107396GB-I00/AEI/10.13039/501100011033 and PID2019-107338RB-C66/AEI/10.13039/501100011033, as well as the Severo Ochoa Program for Centres of Excellence (CEX-2018-000867-S). NK acknowledges the funding from Spanish MICIN through grant PID2019-107338RB-C61/AEI/10.13039/501100011033, as well as a María de Maeztu award to Nanogune, Grant CEX2020-001038-M funded by MICIN/AEI/10.13039/501100011033.