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Infrared Characterization of Hydroxyl Groups on MgO: A Periodic and Cluster Density Functional Theory Study
- Source :
- Journal of the American Chemical Society. 129:6442-6452
- Publication Year :
- 2007
- Publisher :
- American Chemical Society (ACS), 2007.
-
Abstract
- The infrared OH stretching frequencies of the various types of hydroxyl groups on MgO surfaces have been calculated by periodic (VASP) and cluster (Gaussian) DFT simulations. Surface irregularities (mono and diatomic steps, corners, step divacancies, and kinks) have been considered to model the IR spectra of hydroxylated MgO powders. A good correspondence between calculated and experimental frequencies is obtained with the B3LYP functional. Hydrogen-bonding is the parameter which influences most the IR frequency of OH groups, followed by location of OH groups in concave or convex areas of the surface and then oxygen coordination. The evolution of experimental IR spectra upon evacuation at increasing temperature can be rationalized on the basis of calculated thermal stabilities of each kind of OH groups. A new model is finally proposed to help assign the experimental bands, in terms of hydrogen-bonding, local topology of the hydroxylated sites, and coordination of oxygen.
- Subjects :
- Chemistry
Infrared
Gaussian
Infrared spectroscopy
chemistry.chemical_element
General Chemistry
Biochemistry
Oxygen
Diatomic molecule
Catalysis
symbols.namesake
Colloid and Surface Chemistry
Computational chemistry
Thermal
Physics::Atomic and Molecular Clusters
symbols
Cluster (physics)
Physical chemistry
Density functional theory
Physics::Chemical Physics
Subjects
Details
- ISSN :
- 15205126 and 00027863
- Volume :
- 129
- Database :
- OpenAIRE
- Journal :
- Journal of the American Chemical Society
- Accession number :
- edsair.doi.dedup.....3324602fbb4fdab340c703b0cabfddc1