Electronic charge density at nuclear sites in beryllium metal: Dependence on lattice constants

A calculation of the electronic charge density at the nuclear site in beryllium metal as a function of lattice parameters is presented. It is based on an orthogonalized-plane-wave method and it includes changes in unit cell volume by -1 and -2% as well as changes in $\frac{c}{a}$ ratio from the normal pressure value by +1%, 0%, and -1%. For a typical volume change of -2%, the conduction-electron charge density at the nuclear site changes by +1.4%. For the same volume change, the total electron charge density changes by +0.09%.