Homocoordination preference in NaCs and LiNa liquid alloys by first principles molecular dynamics

We present structural and dynamics results based on Hellman-Feynman molecul ar dynamics for the liquid phase of the NaCs alloy at two Na concentrations (c(Na)=0.6 and 0.8) and for the Li0.61Na0.39 zero alloy at two temperature s (T=590 K and 690 K). For NaCs the calculated structure factor S(k) is in very good agreement with data from neutron scattering experiments and the p artial structure factors are compared to semiexperimental, theoretical and classical molecular dynamics predictions. We predict similar values for the self-diffusion coefficients of Na and Cs atoms in the Na0.6Cs0.4 alloy. Fo r LiNa the concentration-concentration structure factor is in good agreemen t with experimental data and our results for the dynamics are compared with data from classical molecular dynamics simulations. (C) 1999 American Inst itute of Physics. [S0021-9606(99)51935-1].