New Framework for Computing a General Local Self-Diffusion Coefficient Using Statistical Mechanics

Widely applicable, modified Green-Kubo expressions for the local diffusion coefficient (D-l) are obtained using linear response theory. In contrast to past definitions in use, these expressions are statistical mechanical results. Molecular simulations of systems with anisotropic diffusion and an inhomogeneous density profile confirm the validity of the results. Diffusion coefficients determined from different expressions in terms of currents and velocity correlations agree in the limit of large systems. Furthermore, they apply to arbitrarily small local regions, making them readily applicable to nanoscale and inhomogeneous systems where knowledge of D-l is important.

Automated summary

This study obtains widely applicable, modified Green-Kubo expressions for calculating the local diffusion coefficient using linear response theory. Molecular simulations confirm the validity of these expressions and indicate their applicability to nanoscale and inhomogeneous systems.