1. General discussions of and references to ab initio calculations are found in: (a) Levine IN (2000) Quantum chemistry, 5th edn. Prentice Hall, Engelwood Cliffs, NJ. (b) Lowe JP (1993) Quantum chemistry, 2nd edn. Academic Press, New York. (c) Pilar FL (1990) Elementary quantum chemistry, 2nd edn. McGraw-Hill, New York. (d) An advanced book: Szabo A, Ostlund NS (1989) Modern quantum chemistry. McGraw-Hill, New York. (e) Foresman JB, Frisch Æ (1996) Exploring chemistry with electronic structure methods. Gaussian Inc., Pittsburgh, PA. (f) Leach AR (2001) Molecular modelling, 2nd edn. Prentice Hall, Essex, England. (g) A useful reference is still: Hehre WJ, Radom L, Schleyer PvR, Pople JA (1986) Ab initio molecular orbital theory. Wiley, New York. (h) An evaluation of the state and future of quantum chemical calculations, with the emphasis on ab initio methods: Head-Gordon M (1996) J Phys Chem 100:13213. (i) Jensen F (2007) Introduction to computational chemistry, 2nd edn. Wiley, Hoboken, NJ. (j) Dewar MJS (1969) The molecular orbital theory of organic chemistry. McGraw-Hill, New York. This book contains many trenchant comments by one of the major contributors to computational chemistry; begins with basic quantum mechanics and ab initio theory, although it later stresses semiempirical theory. (k) Young D (2001) Computational chemistry. A practical guide for applying techniques to real world problems. Wiley, New York. (l) Cramer CJ (2004) Essentials of computational chemistry, 2nd edn. Wiley, Chichester, UK
2. Dewar contests the origin of the term with an amusing anecdote: Dewar MJS (1992) In: Seeman JI (ed) Profiles, pathways and dreams. American Chemical Society, Washington, D.C., p 129
3. Hartree DR (1928) Proc Camb Phil Soc 24:89
4. (a) The relativistic one-electron Schr??dinger equation is called the Dirac equation. It can be used with the Hartree???Fock approach to do Dirac???Fock (Dirac???Hartree???Fock) calculations; see Levine IN (2000) Quantum chemistry, 5th edn. Prentice Hall, Engelwood Cliffs, NJ, pp 602???604.
5. (b) For a brief discussion of spin-orbit interaction see Levine IN (2000) Quantum chemistry, 5th edn. Prentice Hall, Engelwood Cliffs, NJ, loc. cit.