气体分子对甲烷水合物稳定性的影响  

Influence of Gas Molecule on Stability of Methane Hydrate

作　　者：耿春宇[1,2] 丁丽颖[1,2] 韩清珍[1,2] 温浩[1] 

机构地区：[1]中国科学院过程工程研究所,多相反应重点实验室,北京100080 [2]中国科学院研究生院,北京100049

出　　处：《物理化学学报》2008年第4期595-600,共6页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金创新群体(20221603)资助项目

摘　　要：通过B3LYP方法,在6-31G(d,p)水平下,分别优化了结构I型甲烷水合物十二面体和十四面体晶穴结构.结果表明,CH4分子使晶穴的相互作用能降低,增强了晶穴的稳定性.计算了晶穴中甲烷分子C—H键的对称伸缩振动频率,计算结果与实验值相符合.研究发现CH4分子影响晶穴中氧原子的电荷分布,从而增强了氢键的稳定性.通过分子动力学方法研究水合物晶胞中气体分子的占有率对水合物稳定性的影响,进一步说明气体分子对水合物晶穴稳定性的重要作用.In an attempt to probe the influence of gas molecule on stability of methane hydrate, geometry optimizations （by B3LYP/6-31G（d,p）） have been performed on different dodecahedral （H2O20 CH4（H2O20 and tetrakaidecahedral （H2O24, CH4（H2O24 clusters. The result suggested that the CH4（H2O20 and CH4（H2O24 clusters were more stable than the （H2O20 and （H2O24 clusters by calculating interaction energy and Mulliken electron density. It also showed that the CH4 molecule was more important to the stability of methane hydrate. The calculated values of symmetric C--H stretching frequencies of methane were the same as the experimental values in the references. The crystal stability influenced by cage occupancy of hydrate was also simulated by constant-pressure and constant-temperature （NPT） molecular dynamics （MD） method. The result showed that the crystal stability was improved corresponding to the increase of the cage occupancy.

关 键 词：甲烷水合物 量子化学 C-H伸缩振动频率 分子动力学 气体水合物稳定性 

分 类 号：O621.2[理学—有机化学]