组态相互作用方法 (CI) 是一种后Hartree-Fock方法，求解的是多电子体系在波恩-奥本海默近似下的非相对论薛定谔方程。“构型相关”有两层含义：“构型" 从数学角度简洁的表述了它是描述波函的斯雷特行列式的线性耦合。根据轨道占据的规则 (例如, (1s)(2s)(2p)...)，“相关”的意思是不同电子构型（态）之间的混合（相互作用）。由于CI计算的CPU计算时间很长以及需要巨大的硬件资源，所以这个方法只能用于相对较小的体系。

与Hartree-Fock方法相比，为了计入电子相关作用，CI方法使用了由组态态函数（CSF）线性耦合得到的变分波函数，而这些组态态函数是由自旋轨道（用上标SO表示）构建的。

Configuration interaction (CI) is a post-Hartree–Fock linear variational method for solving the nonrelativistic Schrödinger equation within the Born–Oppenheimer approximation for a quantum chemical multi-electron system. Mathematically, configuration simply describes the linear combination of Slater determinants used for the wave function. In terms of a specification of orbital occupation (for instance, (1s)(2s)(2p)...), interaction means the mixing (interaction) of different electronic configurations (states). Due to the long CPU time and large memory required for CI calculations, the method is limited to relatively small systems.