Mass transfer in Frenkel-Kontorova chain initiated by molecule impact

TL;DR

This study investigates how impacts of molecules with varying atom counts initiate crowdions in a Frenkel-Kontorova chain, revealing that molecules with 2 to 9 atoms are more energy-efficient than single atoms for crowdion initiation.

Contribution

It demonstrates that molecules with multiple atoms are more effective than single atoms in initiating crowdions due to their ability to excite wider, lower-velocity crowdions with less energy.

Findings

Molecules with 2-9 atoms are more efficient than single atoms in initiating crowdions.

Finite-length molecules can excite wider crowdions at lower velocities and energies.

Results provide insights into atomistic mass transfer mechanisms in crystal bombardment.

Abstract

The Frenkel-Kontorova chain with a free end is used to study initiation and propagation of crowdions (anti-kinks) caused by impact of a molecule consisting of K atoms. It is found that molecules with 1 < K < 10 are more efficient in initiation of crowdions as compared to single atom (K = 1) because total energy needed to initiate the crowdions by molecules is smaller. This happens because single atom can initiate in the chain only sharp, fast-moving crowdions that requires a relatively large energy. Molecule has finite length, that is why it is able to excite a wider crowdion with a smaller velocity and smaller energy. Our results can shed light on the atomistic mechanisms of mass transfer in crystals subject to atom and molecule bombardment.