Structural Characterization of Sulfur-Containing Water Clusters Using a Density-Functional Based Tight-Binding Approach.
A global optimization search of low-energy isomers is carried out to investigate the structural and stability properties of sulfur-containing water clusters, including both (H2O)nSO42-and (H2O)nH2SO4aggregates. The systematic optimization algorithm involves a combination of parallel-tempering molecular dynamics and periodic gradient-driven quenches with energy and energy-gradient calculations performed using the Self-Consistent-Charge Density-Functional based Tight-Binding (SCC-DFTB) scheme. Comparisons with new MP2 and DFT calculations on the smallest systems and previous ab initio investigations of the literature show that the SCC-DFTB approach provides a fairly accurate description of both neutral and ionic species, comparable to that of DFT. Structural and stability features of larger sulfur-containing clusters, with up to 20 water molecules, are also determined using the SCC-DFTB scheme. The interest of this work is 2-fold: (i) the benchmark on small species demonstrates the ability of SCC-DFTB to describe complex potential energy landscapes involving hydrogen-bonds and proton transfers; (ii) it opens the way to the study of large clusters that can hardly be performed within ab initio approaches.
Laboratoire de Chimie et Physique Quantiques (LCPQ), Université de Toulouse III [UPS] and CNRS , 118 Route de Narbonne, F-31062 Toulouse, France.
Kseniia A
KA
Korchagina
Laboratoire de Chimie et Physique Quantiques (LCPQ), Université de Toulouse III [UPS] and CNRS , 118 Route de Narbonne, F-31062 Toulouse, France.
Aude
A
Simon
Laboratoire de Chimie et Physique Quantiques (LCPQ), Université de Toulouse III [UPS] and CNRS , 118 Route de Narbonne, F-31062 Toulouse, France.
Mathias
M
Rapacioli
Laboratoire de Chimie et Physique Quantiques (LCPQ), Université de Toulouse III [UPS] and CNRS , 118 Route de Narbonne, F-31062 Toulouse, France.
Fernand
F
Spiegelman
Laboratoire de Chimie et Physique Quantiques (LCPQ), Université de Toulouse III [UPS] and CNRS , 118 Route de Narbonne, F-31062 Toulouse, France.
Jérôme
J
Cuny