“…These interfacial tensions determine the wetting angle through the well-known Young equation: In the absence of a well-tested set of force fields for CO 2 -water-mineral wettability studies, Iglauer et al (2012b) used a combination of CO 2 and water models (EPM2, TIP4P/2005) that predicts γ wg within ~10 mN m −1 (Nielsen et al 2012), but they selected a silica-water interaction model (van Beest et al 1990) that overestimates the strength of the silica-water interaction (in the absence of CO 2 , they predicted θ = 0° for water on a silica surface that carries only siloxane functional groups, whereas the experimental value for a fully dehydroxylated silica surface is about 42°; Lamb and Furlong 1982). Bagherzadeh et al (2012) used a water model (TIP4P/Ice) that significantly overestimates the surface tension of liquid water (Vega and de Miguel 2007) and a silica-water interaction model (Lopes et al 2006) that was not designed for use with the TIP4P/Ice water model and that performs less than optimally when used with at least one other water model (Skelton et al 2011). In recent years, the CLAYFF model (Cygan et al 2004b) has emerged as a remarkably accurate model of the interaction between silicate minerals and liquid water (Bourg and Sposito 2010;Ferrage et al 2011;Marry et al 2011;Skelton et al 2011;Bourg and Steefel 2012;Leroch and Wendland 2012), but this model has been exclusively used with two water models (the SPC and SPC/E water models; Berendsen et al 1981Berendsen et al , 1987) that underestimate the surface tension of liquid water (Vega and de Miguel 2007;Nielsen et al 2012).…”