Zero-temperature equation of state of metals in the statistical model with density gradient correction

The density gradient correction to kinetic energy (nine times smaller than the original von Weizsäcker correction) has been used within local density formalism to calculate the cold compression curve of metals. Numerical results are reported for Li, Be, Al and Cu. The modifications to the Thomas-Fermi-Dirac (TFD) results strongly depend, in the low compression range (ϱ/ϱ0 ⩽ 5), on the electron density of the material. The relative difference between the pressures in the present model and the TFD model regularly decreases with increasing compression, suggesting that TFD is reliable for ϱ/ϱ0 ⩾ 50 in Li, ϱϱ0 ⩾ 20 in Be and Al and ϱ/ϱ0 ⩾ 10 in Cu.