The quantum hydrodynamic theory is a promising method for describing microscopic details of macroscopic systems. The hydrodynamic equation can be partially obtained from a single-particle Kohn-Sham equation and improved by adding a viscoelastic kinetic-exchange-correlation tensor term, so that broadening of collective excitation can be taken into account, as well as a correction to the plasmon dispersion. The result is an accurate self-consistent and computationally efficient hydrodynamic description of the free-electron gas. A very accurate agreement with full quantum calculations is shown.

• Received 18 July 2016
• Revised 6 June 2017

DOI:https://doi.org/10.1103/PhysRevB.95.245434