MUlti Site Complexation model

At present the MUSIC (MUlti Site Complexation) model [13,14] can, in principle, explain differences in PZC values for different samples however, for goethite, the variation shown in Fig. 1 is too laige to be explained by the MUSIC model alone based on the current knowledge. 

Hiemstra also emphasises surfaces heterogeneity by noting that (a) the surface planes may contain more than one type of surface oxygens and (b) crystalline metal oxides expose different crystal planes to the solution and these planes will, in general, have different surface groups. For an appropriate description of the protonation of oxide surfaces the multi site type (multifunctional) nature is thus essential and the authors have called their model MUSIC, an acronym for multi site complexation. For optimal use of MUSIC the intrinsic protonation constants have to be known a priori. 

Bickmore, B.R., Rosso, K.M., and Mitchell, S.C., Is there hope for multi-site complexation (MUSIC) modehng in Surface Complexation Modelling, Lutzenkirchen, J., ed., Elsevier, Amsterdam, 2006, p. 269. 

Weerasooriya. R., Aluthpatabendi, I), and Tobschall, H.J., Charge distribution multi-site complexation (CD-MUSIC) modeling of Pb(II) adsorption on gibbsite. Colloids Surf. A. 189, 131, 2001. 

Kulik, D. A., 2002, Gibbs energy minimization approach to model sorption equilibria at the mineral-water interface Thermodynamic relations for multi-site-surface complexation. American Journal of Science 302,227-279. ... 

The emphasis in the previous sections has been on the accuracy with which the Gibbs energy, particularly the entropy component above T , can be calculated. However, as the number of components, C, and the number of atoms in the chosen cluster, n, increases, the number of simultaneous equations that have to be solved is of the order of C". This number is not materially reduced by redefining the equations in terms of multi-site correlation functions (Kikuchi and Sato 1974). The position may be eased as extra computing power becomes available, but a choice will inevitably have to be made between supporting a more complex model or extending a simpler model to a greater number of components. 

Allmendinger M (2004) PhD Thesis. Multi-Site Catalysis - Novel Strategies to Biodegradable Polyesters from Epoxides/CO and Macrocyclic Complexes as Enzyme Models. Universitat Ulm, Ulm... 

Multi-site reactions are important in heterogeneous catalysis, and it is likely that more than one metal center is needed to effect sulfur removal from organic molecules. Therefore, binuclear or polynuclear metal complexes are of interest in modeling HDS reactions in solution. Thiophenes interact with Fe3(CO)i2 in refluxing benzene to produce thiaferroles 30 through metal insertion into the less hindered G-S bond of the thiophene. The... 

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