SEARCH Articles Figures Tables Basis-Set Expansions of Relativistic Electronic Wave Functions Coupled Electron Pair and Cluster Expansions Economical description of electron SDTQ-CI expansions Electron correlation expansion, independent particle model Electron self-energy potential expansion Electronic density Taylor series expansion Electronic state adiabatic representation Born-Huang expansion Electronic states Born-Huang expansion Electronic states partial wave expansion Expansion valve electronic Fourier Expansion of the Electron Density Plane-Wave Expansion - The Free-Electron Models