Experimental, semi-experimental and ab initio equilibrium structures

Abstract

The determination of equilibrium structures of molecules by spectroscopic methods or by quantum mechanical calculations is reviewed. The following structures are described in detail: experimental equilibrium structures, empirical structures, semi-experimental structures and ab initio structures. The approximations made by the different methods are discussed and their accuracies are compared.

Keywords:

• Equilibrium structure
• Ab initio
• Spectroscopy

Acknowledgements

I thank Professor H.D. Rudolph for many helpful suggestions, Professor A.G. Császár, Dr C. Gutle and Professor J. Liévin for critical reading of the manuscript and Professors J.E. Boggs and M. Herman for their encouragement.

Notes

¹ The interactions of the magnetic and electric moments of the nuclei with the other electric and magnetic moments in the molecule may lead to a splitting of the energy levels in several hyperfine components but they do not affect the following discussion.