Ab initio quantum chemistry methods are
computational chemistry methods based on
quantum chemistry. The term
ab initio was first used in quantum chemistry by
Robert Parr and coworkers, including
David Craig in a
semiempirical study on the excited states of benzene. The background is described by Parr. In its modern meaning ('from first principles of quantum mechanics') the term was used by Chen (when quoting an unpublished 1955 MIT report by Allen and Nesbet), by Roothaan and, in the title of an article, by Allen and Karo, who also clearly define it.