
The density-functional free energy can be written in a form that is stationary with respect to variations in the occupation function. For this reason it is useful to look for approximate occupation functions that are sufficiently close to the Fermi function that accuracy is not compromised and yet have advantages for computation. From a computational point of view it is useful to reduce the number of poles of the occupation function in the upper half of the complex energy plane and to locate the poles as far from the real axis as possible. A family of approximate occupation functions that economize computation is introduced. Their properties are discussed and illustrated for a model system.
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 12 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Average | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Top 10% | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Average |
