Diffusion coefficients of Mg isotopes in MgSiO3 and Mg2SiO4 melts calculated by first-principles molecular dynamics simulations

摘要

The mass dependence of diffusion coefficient (D) can be described in the form of D-i/D-j = (m(j)/m(i))(beta) where m denotes masses of isotope i and j, and beta is an empirical parameter as used to quantify the diffusive transport of isotopes. Recent advances in computation techniques allow theoretically calculation of b values. Here, we apply first-principles Born-Oppenheimer molecular dynamics (MD) and pseudo-isotope method (taking m(j)/m(i) = 1/24, 6/24, 48/24, 120/24) to estimate beta for MgSiO3 and Mg2SiO4 melts.