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Development of an empirical force field for silica. Application to the quartz-water interface.

Authors
Lopes-PEM; Murashov-V; Tazi-M; Demchuk-E; MacKerell-AD
Source
J Phys Chem B Condens Mater Surf Interfaces Biophys 2006 Feb; 110(6):2782-2792
NIOSHTIC No.
20029684
Abstract
Interactions of pulverized crystalline silica with biological systems, including the lungs, cause cell damage, inflammation, and apoptosis. To allow computational atomistic modeling of these pathogenic processes, including interactions between silica surfaces and biological molecules, new parameters for quartz, compatible with the CHARMM empirical force field were developed. Parameters were optimized to reproduce the experimental geometry of alpha-quartz, ab initio vibrational spectra, and interactions between model compounds and water. The newly developed force field was used to study interactions of water with two singular surfaces of alpha-quartz, (011) and (100). Properties monitored and analyzed include the variation of the density of water molecules in the plane perpendicular to the surface, disruption of the water H-bond network upon adsorption, and space-time correlations of water oxygen atoms in terms of Van Hove self-correlation functions. The vibrational density of states spectra of water in confined compartments were also computed and compared with experimental neutron-scattering results. Both the attenuation and shifting to higher frequencies of the hindered translational peaks upon confinement are clearly reproduced by the model. However, an upshift of librational peaks under the conditions of model confinement still remains underrepresented at the current empirical level.
Keywords
Silica-dusts; Silicates; Quartz-dust; Models; Biological-systems; Cell-damage
Contact
Division of Toxicology and Environmental Medicine, Agency for Toxic Substances and Disease Registry (ATSDR/CDC), 1600 Clifton Road NE, F-32, Atlanta, Georgia 30333
CODEN
JPCBFK
CAS No.
14808-60-7
Publication Date
20060201
Document Type
Journal Article
Fiscal Year
2006
NTIS Accession No.
NTIS Price
Issue of Publication
6
ISSN
1520-6106
NIOSH Division
OD
Source Name
The Journal of Physical Chemistry, Part B. Condensed Matter, Materials, Surfaces, Interfaces & Biophysical
State
WV; MD; GA
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