Employing Theories Far beyond Their Limits - Linear Dichroism Theory

Chemphyschem : a European Journal of Chemical Physics and Physical Chemistry
Thomas G Mayerhöfer

Abstract

Using linear polarized light, it is possible in case of ordered structures, such as stretched polymers or single crystals, to determine the orientation of the transition moments of electronic and vibrational transitions. This not only helps to resolve overlapping bands, but also assigning the symmetry species of the transitions and to elucidate the structure. To perform spectral evaluation quantitatively, a sometimes "Linear Dichroism Theory" called approach is very often used. This approach links the relative orientation of the transition moment and polarization direction to the quantity absorbance. This linkage is highly questionable for several reasons. First of all, absorbance is a quantity that is by its definition not compatible with Maxwell's equations. Furthermore, absorbance seems not to be the quantity which is generally compatible with linear dichroism theory. In addition, linear dichroism theory disregards that it is not only the angle between transition moment and polarization direction, but also the angle between sample surface and transition moment, that influences band shape and intensity. Accordingly, the often invoked "magic angle" has never existed and the orientation distribution influences spectra to a much...Continue Reading

References

Jan 4, 2008·Applied Spectroscopy·Vasilis G GregoriouStavros T Bollas
Mar 19, 2016·Chemphyschem : a European Journal of Chemical Physics and Physical Chemistry·Thomas G MayerhöferJürgen Popp
Apr 9, 2016·Physical Review Letters·Christian KranertMarius Grundmann
Mar 9, 2017·Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy·Sonja HöferThomas G Mayerhöfer
Jun 5, 2017·Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy·Sonja HöferThomas G Mayerhöfer
Aug 5, 2017·Chemphyschem : a European Journal of Chemical Physics and Physical Chemistry·Thomas G MayerhöferJürgen Popp
Oct 20, 2017·Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy·Thomas G Mayerhöfer, Jürgen Popp

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Citations

Jun 27, 2020·Applied Spectroscopy·Thomas G Mayerhöfer, Jürgen Popp
Jul 15, 2020·Chemphyschem : a European Journal of Chemical Physics and Physical Chemistry·Thomas G MayerhöferJürgen Popp
Aug 29, 2021·Polymers·Petr SedlakPetr Kubersky

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