摘要
在密度泛函 (DFT)B3LYP/ 6_311+ +G( 3d ,3p)水平 ,对中性甘氨酸的最小点结构Ip和H2 O分子间可能存在的氢键复合物进行全自由度能量梯度优化 ,发现了三个氢键极小结构A、C和E ,其中结构A为最稳定结构 ,它是H2 O与甘氨酸的羧基 ( -COOH)形成两个氢键的结构 ,具有C1对称性。分别采用密度泛函理论 (DFT)和MP2方法 ,在 6 - 311+ +G( 3d ,3p)水平 ,对结构A的结构和结合能进行了比较计算 ,得到结合能ΔEDFT为 - 4 1.88kJ/mol,ΔEMP2 为 - 4 0 .34kJ/mol。
the interaction between the global minimum of nonionized glycine (Ip) and H 2O was investigated employing density functional theory (DFT) and MP2 theoretical methods, using Pople's standard 6-311++G(3d,3p) basis set. Three equilibrium structures (A, C and E) of the glycine (Ip) and H 2O complex were finally obtained. The conformer A, which H 2O is internally doubly H bonded to the carboxyl of glycine, is the most stable one among the three condormers. The geometry and the binding energy of A were calculated at DFT/B3LYP and MP2 theory levels. The binding energy of A were calculated at DFT/B3LYP and MP2 theory levels. The binding energy is -41.88 kJ/mol at the DFT/B3LYP and -40.34 kJ/mol at the MP2 level, respectively.
出处
《原子与分子物理学报》
CAS
CSCD
北大核心
2003年第2期275-279,共5页
Journal of Atomic and Molecular Physics
