用密度泛函理论研究氨质子化团簇(NH3)nH^＋(n=1～8)的结构  

Studying the structures of protonated ammonia clusters(NH_3)~nH^+(n=1～8)with density functional theory

作　　者：孙志青[1] 孔祥和[1] 刘存海[1] 乔光[2] 张良芳[1] 张树东[1] 

机构地区：[1]曲阜师范大学物理工程学院,曲阜273165 [2]西华师范大学物理与电子信息学院,南充637002

出　　处：《原子与分子物理学报》2008年第2期427-432,共6页Journal of Atomic and Molecular Physics

摘　　要：运用Gaussian03W程序中的密度泛函B3LYP方法,在6-31+G(d)基组水平上对氨质子化团簇(NH3)nH+(n=1～8)的可能的几何构型进行了结构优化,得到了该系列团簇的稳定结构及其对应的总能量.结果表明,氨质子化团簇的稳定结构是质子与一个氨分子结合形成一个NH4+离子核,其它氨分子通过氢键作用形成氨链后与该离子核的四个氢以氢键结合形成的,它们之间的结合力均为中强氢键.另外,我们还利用能量的二阶差分理论对团簇的稳定性进行了研究,并计算了团簇的平均束缚能,发现随着团簇尺寸的增大,团簇的平均束缚能逐渐减小.A series of stable structures of the protonated ammonia clusters（NH3）nH^＋（n=1～8） and their total energies are obtained,after possible geometries have been optimized with the Gaussian 03W suite of programs using density functional theory with the B3LYP functional and the 6-31＋G（d） basis set.The result shows that a proton and an ammonia molecule form an NH4^＋ core ion,and the other ammonia molecules are bound to four H of this core ion by hydrogen bonds in the form of ammonia chains.All the hydrogen bonds are mezzo forte ones.Besides,the stability of the clusters is studied with the second difference of the energies.Finally,the average binding energies were caculated,and the result shows that the average binding energies decrease with the increasing of clusters size.

关 键 词：氨质子化团簇 氢键 B3LYP方法 

分 类 号：O641[理学—物理化学]