On the local density dependence of electronic stopping of ions in solids

Journal Article · 17 April 2018 · Journal of Nuclear Materials

DOI: https://doi.org/10.1016/j.jnucmat.2018.04.019 · OSTI ID:1512617

Caro, M. ^[1]; Tamm, A.  ^[2]; Correa, A. A. ^[2]; Caro, A. ^[3]

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1. Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States). Dept. of Mechanical Engineering
2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Quantum Simulations Group
3. George Washington Univ., Ashburn, VA (United States). Science and Technology Center

We use here time-dependent density functional theory to calculate the electronic stopping S_e in binary Ni-Ni atomic collisions and for a Ni projectile along channeling directions in a Ni crystal. Our results show that when S_e is reported as a function of the ground state target electronic density ρ₀ the stopping is not a single-valued function of the local density, as assumed in formalisms that date back to the origins of quantum mechanics, but shows loops, suggesting that it is inaccurate to model stopping as a dissipative force of the type $\text{F}=\beta \left({\rho }_0\right)\text{v}$, as it is customarily done in non-adiabatic molecular dynamics simulations of ion-solid interactions. We compare our results with S_e in a uniform electron gas where the above definition for the force holds, and conclude on the validity of using jellium as a crude approximation for more realistic inhomogeneous electron gases.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Energy Dissipation to Defect Evolution (EDDE); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC52-07NA27344
• OSTI ID: 1512617
• Report Number(s): LLNL-JRNL--771401; 962525
• Journal Information: Journal of Nuclear Materials, Journal Name: Journal of Nuclear Materials Vol. 507; ISSN 0022-3115
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English