The Theory Study On Properties Of Be_n(n=2-8) Clusters In Terms Of Molecular Face Theory And Ab Initio Method

In this paper, Molecular face theory proposed by Yang et al is applied mainly. Firstly, the simplest Be₂ dimmer of alkaline-earth metals is studied in detail. Its Molecular Intrinsic Characteristic Contour parameters are gained. Under its singlet and triplet states, the changing trend of the electron density with the changes of energy and nuclear spacing was analyzed. At the same time, the forming reasons of the different Molecular Face of Be₂ dimmer are analyzed under the different nuclear spacing. Secondly, stable geometrical structures and the possible existent isomers of Be_n(n=3-8) clusters have been obtained by Gaussian(03) optimization. Molecular Faces and corresponding parameters of stable structures and isomers of Be₃ and Be₄ has been gained by Molecular Face Theory For Be_n(n=5-8), their structures and properties are studied mostly, especially, Be₆. The influence of spin multiplicity on the various isomers of clusters is considered, the isomers of the higher spin multiplicity are obtained. Detailed contents are as follows:1 The relations of Be₂ dimmer energy and nuclear spacing, the ionization energy and nuclear distance were studied by MP2, HF and B3LYP under the same set 6-311++G (3df,3pd). The Molecular Face figures of Be₂ under the different nuclear spacing are obtained by MELD exact Ab initio CISD/6-31+G** and our compiled PAEM program, and electron density of the Molecular Intrinsic Characteristic Contour are vividly revealed. the forming reasons of the different Molecular Face of Be₂ dimmer are analyzed under the different nuclear spacing. It establishes a foundation for studying the bigger Be_n clusters.2 Stable geometrical structures and the possible existent isomers of Be_n(n =3-8) clusters have been obtained by MP2/6-311++G(3df,3pd) optimization. The Molecular Faces of stable geometrical structures and the possible existent isomers of Be₃ and Be₄ are obtained by our compiled PAEM program with the help of Matlab8.0. Their Molecular Intrinsic Characteristic Contour parameters are gained. The influence of spin multiplicity on the various isomers of clusters is considered, the isomers of the higher spin multiplicity are obtained. The structures and properties of stable geometrical structures and the possible existent isomers of Be₆ are studied importantly, its fourteen geometrical structures are obtained, eight kinds of structures are not mentioned in the previous literatures, some structures are stable. The corresponding data of the simulating eight structures enrich the isomers theory of Be₆ clusters and farther afford reliable reference value.