Standard Article

Fundamentals of Electronic Spectroscopy

  1. Hans J. Wörner1,2,
  2. Frédéric Merkt1

Published Online: 15 SEP 2011

DOI: 10.1002/9780470749593.hrs069

Handbook of High-resolution Spectroscopy

Handbook of High-resolution Spectroscopy

How to Cite

Wörner, H. J. and Merkt, F. 2011. Fundamentals of Electronic Spectroscopy. Handbook of High-resolution Spectroscopy. .

Author Information

  1. 1

    Laboratorium für Physikalische Chemie, ETH Zürich, Zürich, Switzerland

  2. 2

    National Research Council of Canada and University of Ottawa, Joint Laboratory for Attosecond Science, Ottawa, Ontario, Canada

Publication History

  1. Published Online: 15 SEP 2011


The basic principles of electronic spectroscopy of atoms and molecules in the gas phase are presented. In the first part, the elementary concepts necessary to describe the electronic structure of atoms, diatomic molecules, and polyatomic molecules are introduced in a systematic manner, with an effort to classify the different interactions (electrostatic, spin–orbit, hyperfine) and types of motions (electronic, vibrational, rotational), which determine the energy level structures. In the second part, electronic transitions are discussed, with their spin-rovibrational structures. Examples ranging from the simple band structure of equation image electronic transitions of homonuclear diatomic molecules to the highly complex band structure of polyatomic molecules subject to strong vibronic interactions are used to illustrate the richness of electronic spectra.


  • electronic spectra;
  • Born–Oppenheimer approximation;
  • selection rules and group theory;
  • Jahn–Teller effect;
  • Renner–Teller effect;
  • Hund's angular momentum coupling cases;
  • spin–orbit coupling, LS and jj coupling;
  • autoionization;
  • predissociation;
  • intersystem crossing;
  • internal conversion;
  • Franck–Condon factors;
  • exciton model;
  • Herzberg–Teller intensity borrowing mechanism;
  • Rydberg states;
  • valence states;
  • ion-pair states;
  • diatomic molecules;
  • atomic spectroscopy;
  • Zeeman and Stark effects;
  • hyperfine coupling;
  • atomic and molecular orbitals;
  • Hückel molecular orbitals;
  • Frost–Musulin diagram;
  • Walsh diagram;
  • nonradiative transitions;
  • correlation diagrams