Details
| Original language | English |
|---|---|
| Pages (from-to) | 8143-8150 |
| Number of pages | 8 |
| Journal | Journal of Chemical Physics |
| Volume | 104 |
| Issue number | 20 |
| Publication status | Published - 22 May 1996 |
| Externally published | Yes |
Abstract
The anthraquinone dye molecule quinizarin is known to allow for persistent spectral hole burning up to liquid nitrogen temperatures after chemisorption on alumina surfaces. The mechanism underlying these improved hole-burning properties is not known, though is has been speculated that it might be related to intrinsic surface effects on the electronic structure of the dye. We approach this problem theoretically using gradient corrected density functional theory. The chemisorbed compound system is modelled by a periodically replicated nine layer slab which represents the (0001) surface of α-Al2O3. The chemisorption geometry obtained by geometry optimization and confirmed by Car-Parrinello molecular dynamics runs at room temperature is shown to be a perpendicular arrangement of quinizarin on the surface, where a chelate-like bond is formed with one exposed surface aluminum atom. In order to get information about the electronic structure, the frontier orbitals that are relevant for the description of the electronic excitation to the first excited state are evaluated for the isolated molecule, the chemisorbed molecule, and a quinizarin-aluminum-water complex. The strong red shift of the absorption frequency found in experiment upon chemisorption is reproduced. However, the results show that the shape of the frontier orbitals and hence the properties of the electronic excitation remain essentially unchanged by chemisorption. Thus, the differences in the behavior of the isolated and the chemisorbed dye observed in persistent spectral hole-burning experiments cannot be explained by genuine surface induced effects on the molecular electronic structure.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- General Physics and Astronomy
- Chemistry(all)
- Physical and Theoretical Chemistry
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In: Journal of Chemical Physics, Vol. 104, No. 20, 22.05.1996, p. 8143-8150.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Structure and electronic properties of quinizarin chemisorbed on alumina
AU - Frank, Irmgard
AU - Marx, Dominik
AU - Parrinello, Michele
PY - 1996/5/22
Y1 - 1996/5/22
N2 - The anthraquinone dye molecule quinizarin is known to allow for persistent spectral hole burning up to liquid nitrogen temperatures after chemisorption on alumina surfaces. The mechanism underlying these improved hole-burning properties is not known, though is has been speculated that it might be related to intrinsic surface effects on the electronic structure of the dye. We approach this problem theoretically using gradient corrected density functional theory. The chemisorbed compound system is modelled by a periodically replicated nine layer slab which represents the (0001) surface of α-Al2O3. The chemisorption geometry obtained by geometry optimization and confirmed by Car-Parrinello molecular dynamics runs at room temperature is shown to be a perpendicular arrangement of quinizarin on the surface, where a chelate-like bond is formed with one exposed surface aluminum atom. In order to get information about the electronic structure, the frontier orbitals that are relevant for the description of the electronic excitation to the first excited state are evaluated for the isolated molecule, the chemisorbed molecule, and a quinizarin-aluminum-water complex. The strong red shift of the absorption frequency found in experiment upon chemisorption is reproduced. However, the results show that the shape of the frontier orbitals and hence the properties of the electronic excitation remain essentially unchanged by chemisorption. Thus, the differences in the behavior of the isolated and the chemisorbed dye observed in persistent spectral hole-burning experiments cannot be explained by genuine surface induced effects on the molecular electronic structure.
AB - The anthraquinone dye molecule quinizarin is known to allow for persistent spectral hole burning up to liquid nitrogen temperatures after chemisorption on alumina surfaces. The mechanism underlying these improved hole-burning properties is not known, though is has been speculated that it might be related to intrinsic surface effects on the electronic structure of the dye. We approach this problem theoretically using gradient corrected density functional theory. The chemisorbed compound system is modelled by a periodically replicated nine layer slab which represents the (0001) surface of α-Al2O3. The chemisorption geometry obtained by geometry optimization and confirmed by Car-Parrinello molecular dynamics runs at room temperature is shown to be a perpendicular arrangement of quinizarin on the surface, where a chelate-like bond is formed with one exposed surface aluminum atom. In order to get information about the electronic structure, the frontier orbitals that are relevant for the description of the electronic excitation to the first excited state are evaluated for the isolated molecule, the chemisorbed molecule, and a quinizarin-aluminum-water complex. The strong red shift of the absorption frequency found in experiment upon chemisorption is reproduced. However, the results show that the shape of the frontier orbitals and hence the properties of the electronic excitation remain essentially unchanged by chemisorption. Thus, the differences in the behavior of the isolated and the chemisorbed dye observed in persistent spectral hole-burning experiments cannot be explained by genuine surface induced effects on the molecular electronic structure.
UR - http://www.scopus.com/inward/record.url?scp=0000543828&partnerID=8YFLogxK
U2 - 10.1063/1.471490
DO - 10.1063/1.471490
M3 - Article
AN - SCOPUS:0000543828
VL - 104
SP - 8143
EP - 8150
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
SN - 0021-9606
IS - 20
ER -