Surface binding energies of beryllium/tungsten alloys

Binding energies of beryllium and tungsten atoms on surfaces of the alloys Be₂W and Be₁₂W were obtained from density functional theory calculations. Values of 4.08–5.63 eV for beryllium and 6.81–10.04 eV for tungsten were obtained. An analytical force field agrees for beryllium, but its tungsten surface atoms are too strongly bound. The surface binding energies of Be and W on Be₁₂W surfaces is slightly smaller than on the pure Be and W surfaces, respectively. For higher tungsten content, i.e. for Be₂W, the situation is more complicated. For some surfaces of this alloy the surface binding energies are enhanced while for others they are diminished, compared to the pure metal surfaces. The dependency of the cohesive energy on the mole fraction follows a linear relationship.