Phase stabilities of theCo3Ti andNi3V alloys

A linear muffin-tin orbitals (LMTO) total-energy calculation has been carried out on the ordered ${\mathrm{Co}}_3$Ti and ${\mathrm{Ni}}_3$V compounds in order to evaluate the relative stability of the L$1_2$ and D$0_{22}$ crystal structures in the $A_3$B-type transition metal alloys. The correct structure was obtained for both the ${\mathrm{Co}}_3$Ti (which occurs as the L$1_2$) and the ${\mathrm{Ni}}_3$V (which occurs as the D$0_{22}$). The calculated structural preferences were further analyzed in terms of the density of states, which indicates that the D$0_{22}$ structure tends to exist when the concentration of valence electrons per atom exceeds 8.65.