Including nonequilibrium interface kinetics in a continuum model for melting nanoscaled particles.

Area of Science:

• Materials Science
• Thermodynamics
• Computational Physics

Background:

• Melting temperature of nanoscaled particles decreases with increasing interface curvature.
• The Gibbs-Thomson law models this, relating melting point depression to curvature and surface tension.
• This law presents singularities for vanishing particle radii and causes unphysical blow-up in continuum models.

Purpose of the Study:

• To investigate the breakdown of the Gibbs-Thomson law for small nanoparticles.
• To develop a regularized continuum model for nanoparticle melting.
• To reconcile theoretical models with experimental observations of nanoparticle melting.

Main Methods:

• Numerical simulations of a modified Gibbs-Thomson law.
• Inclusion of nonequilibrium interface kinetics.
• Analysis of a Stefan-type continuum model.

Main Results:

• The inclusion of nonequilibrium interface kinetics regularizes the continuum model.
• Mathematical blow-up at finite particle radius is suppressed.
• The melting temperature remains finite for all times, allowing complete melting.
• Model results align with experimental findings of abrupt nanoparticle melting.

Conclusions:

• Nonequilibrium interface kinetics are crucial for accurately modeling the melting of nanoscaled particles.
• The regularized model overcomes limitations of the classical Gibbs-Thomson law.
• This approach provides a physically realistic framework for understanding nanoparticle melting phenomena.