http://dspace-roma3.caspur.it:80 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. 2013-05-23T00:28:13Z http://hdl.handle.net/2307/343 <Title>Multiscale Approach to the Structural Study of Water Confined in MCM41</Title> <Authors>Mancinelli, Rosaria; Imberti, Silvia; Soper, A. K.; Liu, K. H.; Mou, C.Y.; Bruni, Fabio; Ricci, Maria Antonietta</Authors> <Issue Date>2009-11-23</Issue Date> <Is part of>Journal of Physical Chemistry B</Is part of> <Volume>113</Volume> <Pages>16169-16177</Pages> <Abstract>We present a protocol for simultaneous structural characterization of aconfined fluid and the confining Substrate, along with the extractionof site-site pair correlation functions of the liquid of interest. Thisis based on neutron diffraction experiments, exploiting where feasiblethe isotopic substitution technique, analyzed through numerical coarsegraining calculations and atomistic simulations. All of the subtletiesof the experimental procedure, the needed ancillary measurements, andthe recipe for tailoring the numerical codes to the real experiment andsample are described in the case of water confined in MCM41-S-15. Inparticular the excluded volume effects and the relevance ofliquid-Substrate cross-correlation terms in the neutron cross sectionare quantitatively discussed. The results obtained for the microscopicstructure of water evidence a non-homogeneous distribution of moleculeswithin the pore, with the presence of water-substrate hydrogen bonds,and a strong distortion of the water-water radial distributionfunctions with respect to those of bulk water extending at least up tothree hydration layers.</Abstract> 2009-11-22T23:00:00Z http://hdl.handle.net/2307/356 <Title>Influence of concentration and anion size on hydration of H+ Ions and water structure</Title> <Authors>Mancinelli, Rosaria; Sodo, Armida; Bruni, Fabio; Ricci, Maria Antonietta; Soper, Aka Alan K</Authors> <Issue Date>2008-09-23</Issue Date> <Is part of>Journal of physical chemistry B</Is part of> <Volume>113</Volume> <Pages>4075-4081</Pages> <Abstract>Neutron diffraction experiments with hydrogen isotope substitution onaqueous solutions of HCl and HBr have been performed at concentrationsranging from 1:17 to 1:83 Solute per water molecules, at ambientconditions. Data are analyzed using the empirical potential structurerefinement technique in order to extract information on both the ionhydration shells and the microscopic structure of the solvent. It isfound that the influence of these solutes on the water structure isless concentration dependent than that of salts or hydroxides. Moreoverprotons readily form a strong H-bond with a water molecule uponsolvation, at all proportions. The majority of them is also bonded viaa longer bond to another water molecule, giving a prepeak in theg(OwOw). At high solute concentration, the second water molecule may beSubstituted by the counterion. In particular at solute concentrationsof the order of 1:17 or higher, all protons have an anion within adistance of 4.5 angstrom.</Abstract> 2008-09-22T22:00:00Z