CALCULATED OPTICAL SPECTRA OF HEAVILY-DOPED MIXED MOLECULAR CRYSTALS: $NAPHTHALENE^{1}B_{2u}$
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Date
1972
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Ohio State University
Abstract
To further our investigations on the electronic states of heavily doped mixed $crystals^{1}$, we have calculated the optical spectra of isotopically mixed crystals of naphthalene, using the recently acquired dispersion $relation.^{2}$ In addition to some calculations using direct diagonalization of a $320 \ \times\ 320$ matrix, a new method, which is a hybrid of NFC (negative factor counting method)$^{3}$ and CPA (coherent potential approximation) has been devised. This method relates the optical spectra directly to the over-all density-of-states function of the mixed crystal. Results indicate that cluster absorptions, which are absent from CPA results, are retrieved here. There is a good correlation between experimental and calculated spectral structures. This theory of optical spectra of disordered systems is of particular interest to the spectroscopist because it gives special consideration to the $K = 0$ component of the density-of-states function at the expense of self-consistency. Further theoretical justification of this approach is being investigated, as well as relationships with other methods, such as the moment method.
Description
$^{1}$ H.K. Hong and G.W. Robinson, J. Chem. Phys. 52, 825 (1970); 54, 1369 (1971). $^{2}$ H.K. Hong and R. Kopelman, J. Chem. Phys. 55, 724 (1971). $^{3}$ H.K. Hong and R. Kopelman, J. Chem. Phys. 55, 5380 (1971).""
Author Institution: Department of Chemistry, University of Michigan
Author Institution: Department of Chemistry, University of Michigan