The combination of density functional theory with other approaches to themany-electron problem through the separation of the electron-electroninteraction into a short-range and a long-range contribution is a promisingmethod, which is raising more and more interest in recent years. In this worksome properties of the corresponding correlation energy functionals are derivedby studying the electron-electron coalescence condition for a modified(long-range-only) interaction. A general relation for the on-top (zeroelectron-electron distance) pair density is derived, and its usefulness isdiscussed with some examples. For the special case of the uniform electron gas,a simple parameterization of the on-top pair density for a long-range onlyinteraction is presented and supported by calculations within the ``extendedOverhauser model''. The results of this work can be used to buildself-interaction corrected short-range correlation energy functionals.
展开▼
