Abstract
The Hohenberg-Kohn theorem is extended to fractional electron number , for an isolated open system described by a statistical mixture. The curve of lowest average energy versus is found to be a series of straight line segments with slope discontinuities at integral . As increases through an integer , the chemical potential and the highest occupied Kohn-Sham orbital energy both jump from to . The exchange-correlation potential jumps by the same constant, and .
- Received 16 August 1982
DOI:https://doi.org/10.1103/PhysRevLett.49.1691
©1982 American Physical Society