Evaluation of exchange-correlation energy, potential, and stress
Evaluation of exchange-correlation energy, potential, and stress
复制标题
交换关联能量、势能和应力的评估
DOI：
--
复制
发表时间：
2001
期刊：
影响因子：
--
通讯作者：
J. Soler
中科院分区：
文献类型：
--
作者：
L. Balbás;J. Martins;J. Soler
我们描述了一种方法来计算交换和相关（XC）的贡献，总能量，有效势，和应力张量的广义梯度近似。我们避免使用${E}_{mathrm{xc}}[ensuremath{
ho}]，$依赖于电子密度的不连续二阶导数$ensuremath{
ho}.$相反，我们首先通过在真实的空间网格中的积分来近似${E}_{mathrm{xc}}$，然后我们计算其相对于网格点处的密度的偏导数。这确保了计算的总能量、势能和应力之间的精确一致性，并且避免了二阶导数的需要。我们展示了该方法的一些应用，它只需要网格中的（自旋）电子密度的值（可能是不均匀的），并返回一个传统的（本地）XC电位。
We describe a method for calculating the exchange and correlation (XC) contributions to the total energy, effective potential, and stress tensor in the generalized gradient approximation. We avoid using the analytical expressions for the functional derivatives of ${E}_{mathrm{xc}}[ensuremath{
ho}],$ which depend on discontinuous second-order derivatives of the electron density $ensuremath{
ho}.$ Instead, we first approximate ${E}_{mathrm{xc}}$ by its integral in a real space grid, and then we evaluate its partial derivatives with respect to the density at the grid points. This ensures the exact consistency between the calculated total energy, potential, and stress, and it avoids the need of second-order derivatives. We show a few applications of the method, which requires only the value of the (spin) electron density in a grid (possibly nonuniform) and returns a conventional (local) XC potential.