The Thomas-Fermi-Dirac (TFD) electronic structure model with the Weizsacker gradient corrections (TFD-W) is employed to calculate the cold equation of state in the Wigner-Seitz spherical-cell approximation. We demonstrate how inclusion of the Weizsacker term removes many of the unphysical features of the TFD lattice model. Results are summarized for seven elements: C612, Mg1224, Fe2656, Ag47108, Au79197, Pb82207, and U92236. Our equation of state (computed using several values of the Weizsacker coupling coefficient) is compared with previous computations and with experimental data. The Weizsacker correction substantially improves the theoretical TFD equation of state at low densities. We also calculate low-mass, equilibrium stellar models constructed from the TFD-W equation of state for carbon. We find that for =1/9 the maximum radius of a carbon white dwarf star is R/R=3.9×10-2 at a mass M/M=2.3×10-3.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics