Stabilizing Capacity of Water Bridges in Nanopore Segments of Humic Substances: A Theoretical Investigation

0333442 - ÚOCHB 2010 RIV US eng J - Journal Article
Aquino, A. J. A. - Tunega, D. - Schaumann, G. E. - Haberhauer, G. - Gerzabek, M. H. - Lischka, Hans
Stabilizing Capacity of Water Bridges in Nanopore Segments of Humic Substances: A Theoretical Investigation.
Journal of Physical Chemistry C. Roč. 113, č. 37 (2009), s. 16468-16475. ISSN 1932-7447. E-ISSN 1932-7455
R&D Projects: GA MŠMT LC512
Grant - others:ASF(AT) P20893-N19
Institutional research plan: CEZ:AV0Z40550506
Keywords : humanic substances * density functional theory * molecular dynamics simulations
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 4.224, year: 2009

Molecular simulations using density functional theory (DFT/PBE and DFT/tight-binding (DFTB)) have been performed to study wetting processes of model nanopore segments in humic substances (HS). A complex of two poly trimers (TC) arranged in parallel alignment was used to provide the structural example for supramolecular contact of two HS chains by means of hydrogen bonds. Geometry optimizations and molecular dynamics simulations were used to investigate the hydrogen-bonded structures formed and to compute their energetic stabilities. At shorter distance between the two oligomer chains an outer solvation was most stable. However, with increasing distance of the two TC the water molecules penetrated into the inside of the created free space, krepiny the two chains together by means of a hydrogen-bonded network. The present model strongly supports the hypothesized bridging function of water molecules in HS provided a local distribution of appropriate functional groups is available.
Permanent Link: http://hdl.handle.net/11104/0178420