N-脒基脲二硝酰胺盐晶体形貌的分子动力学研究

采用分子动力学方法,在正侧(NVT)系综下研究了N-脒基脲二硝酰胺盐(FOX-12)在溶剂中的晶体形貌.通过构建溶剂分子层-晶面的界面吸附模型模拟其动力学平衡构型,计算溶剂与晶体表面间的结合能,进而对真空附着能进行修正并获得溶剂条件下的晶貌.使用自然冷却法在水和水/甲醇中培养FOX-12晶体并利用扫描电子显微镜进行了表征.结果表明,在真空条件下决定FOX-12晶貌的6个重要晶面为(110),(200),(201),(011),(002)和(111);FOX-12在水溶液条件下的主要晶面为(110)和(011),在水/甲醇溶液条件下的主要晶面为(200)和(011),预测的晶体形貌与实验结果相吻合.对水分子和FOX-12的(110)面间的径向分布函数进行了计算,分析了水分子和晶面间的分子间作用力.

Molecular Dynamics Simulations on Crystal Morphology of N-Guanylurea-dinitramide

The crystal morphologies of N-guanylurea-dinitramide(FOX-12) under solvent condition were investigated by molecular dynamics simulation with canonical(NVT) ensemble. The FOX-12 surface-solvent molecule adsorption model was constructed to simulate dynamical equilibrium configuration. By calculating the binding energies of solvent and crystal surfaces, the attachment energies in vacuum were modified and the crystal shapes in different solutions were obtained. The FOX-12 crystals were cultivated in H2O and H2O/MeOH by natural cooling and characterized by scanning electron microscopy. The results show that the morphologically dominant faces of FOX-12 in vacuum are (110), ( 200), ( 201), ( 011), ( 002) and (111); the (110) and (011) faces are found to be the morphologically important growth faces in H2O; the (200) and (011) faces are found to be the morphologically important growth faces in H2O/ MeOH; the predicted crystal morphologies of FOX-12 were in agreement with the experimental results. Furthermore, the radial distribution function(RDF) analyses between H2O molecules and ( 110 ) face of FOX-12 were performed to explore the solvent-crystal interactions.