dorsal/arxiv
View SchemaA First Principles Density-Functional Calculation of the Electronic and Vibrational Structure of the Key Melanin Monomers
| Authors | B. J. Powell, T. Baruah, N. Bernstein, K. Brake, Ross H. McKenzie, P. Meredith, M. R. Pederson |
|---|---|
| Categories | |
| ArXiv ID | q-bio/0401030 |
| URL | https://arxiv.org/abs/q-bio/0401030 |
| DOI | 10.1063/1.1690758 |
| Journal | J. Chem. Phys. 120, 8608 (2004) |
Abstract
We report first principles density functional calculations for hydroquinone (HQ), indolequinone (IQ) and semiquinone (SQ). These molecules are believed to be the basic building blocks of the eumelanins, a class of bio-macromolecules with important biological functions (including photoprotection) and with potential for certain bioengineering applications. We have used the DeltaSCF (difference of self consistent fields) method to study the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), Delta_HL. We show that Delta_HL is similar in IQ and SQ but approximately twice as large in HQ. This may have important implications for our understanding of the observed broad band optical absorption of the eumelanins. The possibility of using this difference in Delta_HL to molecularly engineer the electronic properties of eumelanins is discussed. We calculate the infrared and Raman spectra of the three redox forms from first principles. Each of the molecules have significantly different infrared and Raman signatures, and so these spectra could be used in situ to non-destructively identify the monomeric content of macromolecules. It is hoped that this may be a helpful analytical tool in determining the structure of eumelanin macromolecules and hence in helping to determine the structure-property-function relationships that control the behaviour of the eumelanins.
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"abstract": "We report first principles density functional calculations for hydroquinone\n(HQ), indolequinone (IQ) and semiquinone (SQ). These molecules are believed to\nbe the basic building blocks of the eumelanins, a class of bio-macromolecules\nwith important biological functions (including photoprotection) and with\npotential for certain bioengineering applications. We have used the DeltaSCF\n(difference of self consistent fields) method to study the energy gap between\nthe highest occupied molecular orbital (HOMO) and the lowest unoccupied\nmolecular orbital (LUMO), Delta_HL. We show that Delta_HL is similar in IQ and\nSQ but approximately twice as large in HQ. This may have important implications\nfor our understanding of the observed broad band optical absorption of the\neumelanins. The possibility of using this difference in Delta_HL to molecularly\nengineer the electronic properties of eumelanins is discussed. We calculate the\ninfrared and Raman spectra of the three redox forms from first principles. Each\nof the molecules have significantly different infrared and Raman signatures,\nand so these spectra could be used in situ to non-destructively identify the\nmonomeric content of macromolecules. It is hoped that this may be a helpful\nanalytical tool in determining the structure of eumelanin macromolecules and\nhence in helping to determine the structure-property-function relationships\nthat control the behaviour of the eumelanins.",
"arxiv_id": "q-bio/0401030",
"authors": [
"B. J. Powell",
"T. Baruah",
"N. Bernstein",
"K. Brake",
"Ross H. McKenzie",
"P. Meredith",
"M. R. Pederson"
],
"categories": [
"q-bio.BM",
"cond-mat.mtrl-sci",
"cond-mat.soft",
"physics.bio-ph",
"physics.chem-ph"
],
"doi": "10.1063/1.1690758",
"journal_ref": "J. Chem. Phys. 120, 8608 (2004)",
"title": "A First Principles Density-Functional Calculation of the Electronic and Vibrational Structure of the Key Melanin Monomers",
"url": "https://arxiv.org/abs/q-bio/0401030"
},
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