Theoretical studies on VPI-5. 3. The MS-Q force field for aluminophosphate zeolites

Aluminophosphate zeolite is an artificial material which shows strange hydrophilicity. We have been investigating the reason by quantum mechanics, and found that the hydrophilicity of this zeolite depended on the local geometric deformation, and speculated that the site-specific hydrophilicity might be explained by differences in the stiffness of the local deformation determined by the location with the pore structure. In order to test these ideas, we construct a reliable force field based on the new MS-Q approach developed by Demiralp, Cagin, and Goddard. Our force field well reproduces the experimental structure of VPI-5.