Molecular dynamics of solid solution and coexisting liquid

Two-phase molecular dynamics (MD) simulations of coexisting solid and liquid were performed for binary systems MgO-CaO and NaCl-KCl. Solid solution crystal and its melt having the same composition were placed in a basic cell, and the compositional change of solid and liquid during MD calculation was observed. The starting compositions were Mg-rich (Mg-0.875, Ca-0.125)O, Ca-rich (Mg-0.125, Ca-0.875)O, Na-rich (Na-0.875, K-0.125)Cl, and K-rich (Na-0.125, K-0.875)Cl The concentration of "minor element" in the liquid was detected for some calculations where solid-liquid interface was maintained for a long period of time, more than 400 ps (= 200 x 10(3) steps). These minor elements were swept out into liquid during the growth of the crystal lattice, because of the mismatch of cationic size. It was easier to cause the differentiation in MgO-CaO system than in NaCl-KCl system.