Written to be the definitive text on the rotational spectroscopy of diatomic molecules, this book develops the theory behind the energy levels of diatomic molecules and then summarises the many experimental methods used to study their spectra in the gaseous state. After a general introduction, the methods used to separate nuclear and electronic motions are described. Brown and Carrington then show how the fundamental Dirac and Breit equations may be developed to provide comprehensive descriptions of the kinetic and potential energy terms which govern the behaviour of the electrons. One chapter is devoted solely to angular momentum theory and another describes the development of the so-called effective Hamiltonians used to analyse and understand the experimental spectra of diatomic molecules. The remainder of the book concentrates on experimental methods. This book will be of interest to graduate students and researchers interested in the rotational spectroscopy of diatomic molecules.

• The most comprehensive book on the rotational spectroscopy of diatomic molecules to be published for over 40 years • Provides detailed descriptions of both the theory and experimental techniques involved • Written by leaders in the field

### Contents

1. General introduction; 2. The separation of nuclear and electronic motion; 3. The electronic hamiltonian; 4. Interactions arising from nuclear magnetic and electric moments; 5. Angular momentum theory and spherical tensor algebra; 6. Electronic and vibrational states; 7. Derivation of the effective hamiltonian; 8. Molecular beam magnetic and electric resonance; 9. Microwave and far-infrared magnetic resonance; 10. Pure rotational spectroscopy; 11. Double resonance spectroscopy; Appendices.

### Review

'… the authors are to be congratulated on producing an updates, valuable and comprehensive review of the field.' ChemPhysChem