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The first-principles molecular dynamics study of quartz–water interface



By first-principles molecular dynamics, we have investigated the interaction of quartz (0001) surface with liquid water for two different fresh silica cleavages. The first type of cleavage is terminated by [DOUBLE BOND]Si(O)2 and [DOUBLE BOND]Si for two surfaces, respectively, whereas the second type cleavage has the same termination on both surfaces that consists of [DOUBLE BOND]Si[BOND]O. The water molecules were found to be decomposed and spontaneously form silanol group on both silica surfaces. After 4.0 ps, the chemical reactions were almost saturated. It was found that the silanol groups dominated on both surfaces. For the first type of cleavage, the final structure contains geminal, triple, and single silanols together with peroxy [BOND]Si[BOND]O[BOND]O[BOND]Si[BOND] and [BOND]Si[BOND]O[BOND]O[BOND]H defects. For the second type of cleavage, the final structure contains geminal silanol, single silanol, and siloxane bridge. A small amount of unsaturated sites were also found on both surfaces. Further, we have shown that the newly formed rings at quartz surface range from four- to seven-member ring for both surfaces. All the findings are in good consistent with the recent experimental observations and theoretical respects. © 2012 Wiley Periodicals, Inc.