Irradiation of a metal by lasers or swift heavy ions causes the electrons to become excited. In the vicinity of the excitation, an electronic temperature is established within a thermalization time of 10-100 fs, as a result of electron-electron collisions. For short times, corresponding to less than 1 ps after excitation, the resulting electronic temperature may be orders of magnitude higher than the lattice temperature. During this short time, atoms in the metal experience modified interatomic forces as a result of the excited electrons. These forces can lead to ultrafast nonthermal phenomena such as melting, ablation, laser-induced phase transitions, and modified vibrational properties. We develop an electron-temperature-dependent empirical interatomic potential for tungsten that can be used to model such phenomena using classical molecular dynamics simulations. Finite-temperature density functional theory calculations at high electronic temperatures are used to parametrize the model potential.
Development of an electron-temperature-dependent interatomic potential for molecular dynamics simulation of tungsten under electronic excitation / Khakshouri, S; Alfe, D; Duffy, Dm. - In: PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS. - ISSN 1098-0121. - 78:22(2008). [10.1103/PhysRevB.78.224304]
Development of an electron-temperature-dependent interatomic potential for molecular dynamics simulation of tungsten under electronic excitation
Alfe D;
2008
Abstract
Irradiation of a metal by lasers or swift heavy ions causes the electrons to become excited. In the vicinity of the excitation, an electronic temperature is established within a thermalization time of 10-100 fs, as a result of electron-electron collisions. For short times, corresponding to less than 1 ps after excitation, the resulting electronic temperature may be orders of magnitude higher than the lattice temperature. During this short time, atoms in the metal experience modified interatomic forces as a result of the excited electrons. These forces can lead to ultrafast nonthermal phenomena such as melting, ablation, laser-induced phase transitions, and modified vibrational properties. We develop an electron-temperature-dependent empirical interatomic potential for tungsten that can be used to model such phenomena using classical molecular dynamics simulations. Finite-temperature density functional theory calculations at high electronic temperatures are used to parametrize the model potential.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.