528 research outputs found
Electronic Band Structures of Pristine and Chemically Modified Cellulose Allomorphs
We have investigated the structural properties, vibrational spectra, and
electronic band structures of crystalline cellulose allomorphs and chemically
modified cellulose with quantum chemical methods. The electronic band gaps of
cellulose allomorphs I, I, II, and III lie in the range of
5.0 to 5.6 eV. We show that extra states can be created in the band gap of
cellulose by chemical modification. Experimentally feasible amidation of
cellulose I with aniline or 4,4'- diaminoazobenzene creates narrow
bands in the cellulose band gap, reducing the difference between the occupied
and empty states to 4.0 or 1.8 eV, respectively. The predicted states
4,4'-diaminoazobenzene-modified cellulose I fall in the visible
spectrum, suggesting uses in optical applications.Comment: 15 pages + 11 pages of supporting informatio
An Examination of the Dilution of Waterborne Pollution from the German Bight to the Cattegat by Means of Radioactive Tracers
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