Molecular spectroscopy

The molecular spectroscopy is a collective term of spectroscopic methods , which deals with the interaction of molecules with electromagnetic fields concerned. This includes the excitation of rotation, oscillation and electron states in the molecules. This enables both the characterization of molecular properties such as bond lengths and strengths and the identification of the atomic components.

In contrast to the line spectra of atomic spectroscopy, the observed molecular spectra are so-called band spectra . They consist of individual lines that are so densely clustered that they form compound groups (the " bands "). The bands can in turn overlap. The reason for this is that the molecules can absorb or emit energy not only through electron transitions, but also when the atoms vibrate against each other and when the molecule rotates around one of its axes.

The basic investigations into molecular physics were made at the beginning of the 20th century with high-resolution grating spectral apparatus (see also grating spectrometer ). Today, high-precision investigations on molecules are often carried out using laser spectroscopic methods .

The following methods are part of molecular spectroscopy:

• Electron Spin Resonance (ESR / EPR)
  • Electron-nuclear double resonance (ENDOR)
• Fluorescence spectroscopy
  • Single molecule fluorescence spectroscopy
• Frequency modulation spectroscopy
• Nuclear magnetic resonance spectroscopy (NMR, also high frequency spectroscopy )
• Rotational spectroscopy
• Vibrational spectroscopy
  • high resolution electron energy loss spectroscopy (HREELS)
  • Infrared Spectroscopy (IR)
  • Raman spectroscopy
  • Sum frequency spectroscopy
• UV / VIS spectroscopy (UV / VIS)

literature

German

• Peter M. Skrabal: Spectroscopy, a cross-method representation from the UV to the NMR range . vdf Hochschulverlag AG, Zurich 2009, ISBN 978-3-8252-8355-1 .
• Wolfgang Demtröder : Molecular Physics: Theoretical Foundations and Experimental Methods . 1st edition. Oldenbourg, 2003, ISBN 3-486-24974-6 .
• Hermann hook , Hans Christoph Wolf : atomic and quantum physics. 8th edition. Springer, Berlin 2003, ISBN 3-540-02621-5 .
• Hermann Haken, Hans Christoph Wolf: Molecular Physics and Quantum Chemistry. 5th edition. Springer, Berlin 2006, ISBN 3-540-30314-6 .

English

• Peter W. Atkins, Ronald Friedman: Molecular Quantum Mechanics. 4th edition. Oxford University Press, Oxford 2004, ISBN 0-19-927498-3 .
• Jack D. Graybeal: Molecular Spectroscopy. McGraw-Hill Education, New York NY et al. 1988, ISBN 0-07-024391-3 .
• J. Michael Hollas: Modern Spectroscopy. 4th edition. John Wiley & Sons, Chichester 2003, ISBN 0-470-84416-7 .
• E. Bright Wilson Jr., JC Decius, Paul C. Cross: Molecular Vibrations - The Theory of Infrared and Raman Vibrational Spectra. Dover Publications, New York NY 1980, ISBN 0-486-63941-X .