二次組態相互作用[1]（英語：Quadratic configuration interaction，簡稱QCI）是一種對組態相互作用的擴展[2]，它修正了單、雙激發組態相互作用（CISD）的大小一致性問題[3]。
John A. Pople, Martin Head‐Gordon, and Krishnan Raghavachari. Quadratic configuration interaction. A general technique for determining electron correlation energies. The Journal of Chemical Physics (American Institute of Physics). 1987, 87 (10): 5968–35975. Bibcode:1987JChPh..87.5968P. doi:10.1063/1.453520. David Maurice and Martin Head-Gordon. Analytical second derivatives for excited electronic states using the single excitation configuration interaction method: theory and application to benzo[a]pyrene and chalcone. Molecular Physics (Taylor & Francis). May 10, 1999, 96 (10): 1533–1541. Bibcode:1999MolPh..96.1533M. doi:10.1080/00268979909483096. Martin Head-Gordon, Rudolph J. Rico, Manabu Oumi, and Timothy J. Lee. A doubles correction to electronic excited states from configuration interaction in the space of single substitutions. Chemical Physics Letters (Elsevier). 1994, 219 (1–2): 21–29. Bibcode:1994CPL...219...21H. doi:10.1016/0009-2614(94)00070-0.
