Successful modern generalized gradient approximations (GGA's) are biased toward atomic energies. Restoration of the first-principles gradient expansion for exchange over a wide range of density gradients eliminates this bias. We introduce PBEsol, a revised Perdew-Burke-Ernzerhof GGA that improves equilibrium properties of densely-packed solids and their surfaces.

翻译：成功的现代通用梯度近似值(GGA)偏向于原子能源。 恢复第一原则梯度扩张以交换多种密度梯度,消除了这一偏差。 我们引入了经修改的PBEsol, 即改进密集包装固体及其表面平衡特性的Pardew-Burke-Ernzerhof GGA。