Wigner high electron correlation regime in nonuniform electron density systems: Kinetic and correlation-kinetic aspects

The Wigner high electron correlation regime is characterized in the literature by an electron-interaction energy much greater than the kinetic energy. Via the ‘quantal Newtonian’ first law, we discover that for a nonuniform electron density system in this regime, there is a ‘quantal compression’ of the kinetic energy density. The explanation of this compression provides a fundamental understanding for why the kinetic energy is a smaller fraction of the total energy relative to the same ratio in the low correlation regime. We also discover by application of quantal density functional theory, that the contribution of electron correlations to the kinetic energy – the correlation-kinetic effects – and to the total energy is very significant. We propose that in addition to a high electron-interaction energy, the Wigner regime must thus also be characterized by a high correlation-kinetic energy.