17 KB187 KB16 KB199820252001Dill, Ken A.Kalyuzhnyi, Yura V.Vlachy, Vojkoštevilka:3letnik:488 stranistr. 309-316ISSN:1318-0207COBISSID:23760133URN:URN:NBN:SI:doc-NG9FCSPDenSlovensko kemijsko društvoActa chimica slovenicaCollinsov modelhidratacijamodelipolielektrolitiraztopineHydration of simple ions. Effect of the charge density|Ions are often classified as kosmotropes or chaotropes depending on whether they order or disorder water, as determined by how much they change the viscosity of water. Collins has proposed that water ordering by an ion dependson its charge density, using a simple fused-sphere model (K. D. Collins, Biophys. J., 1997, 72, 65-76). To make his idea more quantitative, we have applied the site-site integral equation of Chandler, Silbey and Ladanyi to obtain the potential of the mean force between ions and water molecules. From the potential of mean force curves we obtain the activation energy for transferring a water molecule from near the ion to the bulk. The result for this quantity are in semi-quantitative agreement with experimental data for alkali halides and with theoretical results based on the TIP3P model of waterV članku so predstavljeni rezultati za preprosti model hidratacije ionov, ki ga je predlagal Collins (K. D. Collins, Biophys. J., 72, 65-76). Ioni so ponazorjeni kot toge kroglice z naboji v središčih, voda pa kot dipol, ki ga sestavljata dve spojeni nabiti togi kroglici. Ustrezno Chandler-Silbey-Ladany integralsko enačbo smo rešili numerično. Izračunali smo potenciale povprečne sile za interacijo med vodo in nekaterimi ioni ter od tod aktivacijsko energijo za prenos vode iz prve hidratne lupine iona v drugo. Rezulati se sorazmerno dobro ujemajo z merskimi podatki in teoretičnimi rezultati, dobljenimi na osnovi bolj realističnega modela vode (model TIP3P). Naši računi potrjujejo smiselnost Collinsovega modela hidratacije, ki predpostavlja, da je gostota naboja izbranega iona tisti parameter, ki določa strukturo in gibljivost vode v njegovi okoliciTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaSlovensko kemijsko društvo