Multi-temperature atomic ensemble: nonequilibrium evolution after ultrafast electronic excitation
arxiv(2024)
摘要
Ultrafast laser radiation or beams of fast charged particles primarily excite
the electronic system of a solid target driving it transiently out of thermal
equilibrium. Apart from the nonequilibrium between the electrons and atoms,
each of the subsystems may themselves be far from equilibrium. We demonstrate
that the transient state of the atomic system may be tracked with the
generalized temperature approach in the configuration and momentum subspaces.
It is shown that the definition of the kinetic temperature of atoms in the
momentum subspace is unaffected by the excitation of the electronic system. We
derive an expression for the configurational atomic temperature when the
electronic temperature differs from the atomic one, applicable to the
electronic-temperature-dependent interatomic potentials (such as ab-initio
molecular dynamics simulations). It is revealed that upon ultrafast
irradiation, the atomic system of a solid exists temporarily in a
multi-temperature state: separate equilibria in the momentum and
configurational subspaces. Complete equilibration between the various atomic
temperatures takes place at longer timescales, forming the energy
equipartition. Based on these results, we propose a formulation of
multi-temperature heat transport equations.
更多查看译文
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要