Early stage of the development of quantum chemistry without spin and its recent applications

AbstractGeneral ideas, on which the quantum chemistry without spin is based, are discussed. Three important applications of quantum chemistry without spin are presented in detail: (1) the methods for finding the molecular spin‐multiplets allowed by the Pauli principle; (2) the symmetry properties of the electron density that determines the Kohn‐Sham equations in the density functional theory; and (3) the foundations of the Pauli principle. In particular, it was demonstrated that, on the one hand, the Pauli exclusion principle cannot be derived from other fundamental principles of quantum mechanics; on the other hand, it cannot be considered as a postulate, since all other symmetry options for the total wave function of identical particles, except the one‐dimensional representations, are forbidden. © 2012 Wiley Periodicals, Inc.This article was published online on 18 June 2012. An error was subsequently identified. This notice is included in the online and print version to indicate that both have been corrected on 25 July 2012.