四钼酸铵结构及稳定性的量子化学计算

来源期刊：中南大学学报(自然科学版)2001年第6期

论文作者：吴争平 尹周澜 陈启元 张平民 李洁

文章页码：591 - 594

关键词：四钼酸铵;结构;稳定性;量子化学

Key words：ammonium tetramolybdate; structure; stability; quantum chemistry

摘    要：用量子化学计算方法RHF3-21G和STO-3G计算了3种可能结构的无水四钼酸铵结晶(NH₄)₄Mo₈O₂₆的总能量和该分子中各原子的净电荷，用分子结构最优化方法中的最速下降法，以均方根梯度0. 42 kj.mol^-1为优化终止条件对该3种不同结构四钼酸铵进行了几何优化．计算模型用CS ChemOffice和HyperChem Pr0 6.0程序绘制并进行几何优化，量子化学计算用Gaussian 98程序完成．计算结果表明：四钼酸铵的3种可能结构中，基本单元MoO₆八面体均有不同程度的扭曲，其中具有8个MoO₆八面体公用棱结构的四钼酸铵中，MoO₆八面体扭曲程度最小，总能量最低，最稳定。

Abstract: The total energy and atomic charges of ammoniumtetramolyb date with three possible structures were computed with RHF/3-21G, STO-3G, and their geometrical structures were optimized using the molecular mechanics optimization method. The algorithm of optimization used in this work is steepest descentmethod and the termination condition is RMS(Root-mean-square) gradient of 0.42 kJ·mol^-1. The calculation modelswere protracted and optimized with CS Chem Office and HyperChem Pro 6.0 programs. All calculation work was accomplished with Gaussian 98 program. The calculated results show that the structure of ammonium tetramolyb date with eight MoO6is relatively stable and its contortion is the smallest.