Study On The Molecular Face Of Small Clusters And The Dynamic Process Of HF And HCHO Combined With H₂O Dimers

Molecular shape and size is one of the most import basic concepts.Molecular face advanced by YANG Zhong-Zhi et al, can not only characterize molecular shape and size,but also characterize the molecular interface electron density distribution.In this paper,we study molecular face of small clusters and explore the molecular face dynamic process of HF and HCHO combined with H2O dimers.The details are as follows:1. Theoretical study on the molecule faces of (MH) n (M = Li, Na, K; n = 1-4)clusters. In the MP2/6-311++G (3df, 3pd) level, we get the low-energy geometry of the clusters of the (MH) n (M = Li, Na, K; n = 1-4), the first ionization energy, binding energy, the polarization rate in the same calculation method and basis set of molecular. By using the CISD in MELD package with the 6-31+G(d,p) basis set combination with our PAEM program, the potential acting on an electron within a molecule (PAEM) were calculated for (MH)n (M=Li, Na, K; n=1?4) clusters. The feature of PAEM for these clusters has been studied. The relationship between the potential saddle of the chemical bond, Dpb and chemical bond has been explored. And we depict their molecular faces . With our definition of the role of clusters tDpb potential barrier can be used to characterize the stability of clusters. Comparing the contours of H atomic regions with the metal atomic regions, we find that their H atomic regions have expanded, whereas their metal atomic regions have shrunk. They reflect that the ability to attract electrons of H atom is stronger than the Li, Na and K atoms.2. Study on the molecule face of A…H₂O(A=CH₃OH, HCHO, HCOOH) dimer. In the MP2/aug-cc-pvdz level, we gain the optimized the low-energy configuration of A…H2O (A=CH₃OH, HCHO, HCOOH) dimers and calculate the first ionization energy of dimer, binding energy, polarization rate. By using the CISD in MELD package with the 6-31+G(d,p) basis set combination with our PAEM program, we has got PAEM and their molecular face. Compared the single-electron potential barrier Dpb along the O(A)…H(H₂O) direction, we gain the fact that the shorter O(A)…H(H₂O) distance, the greater the one-electron potential barrier, the stronger hydrogen bonds, the greater the dimer binding energy.3. HF…H2O dimer and HCHO…H2O dimer dynamic process. In the MP2/6-311++G (3df, 3pd) level, we attain the first ionization energy, binding energy of HF…H2O dimer in different O(H₂O)…H(HF) distance. By using the CISD in MELD package with the 6-31+G(d,p) basis set combination with our in-house program, the potential acting on an electron within a molecule (PAEM) is calculated. In the formation of hydrogen bonds, when the O(H₂O)…H(HF) distance is about 3.00(?), HF…H₂O dimer charge transfer higher. And contours of HF and H₂O begin to overlap when O(H₂O)…H(HF) distance is about 2.48(A). Meanwhile, HCHO…H₂O dimer has done a similar deal.