The B3LYP/6-31G* method was employed to optimize the BeGe8 isomeric structures. Some adsorptive precursors can be formed without experiencing activation energy. Hirshfeld charges and Mayer total valences analysis show that a larger extent of back-donation leading to a higher Be negativity and hypervalency. All Be-Ge bonds are covalent, not ionic, according to charge partitions and M.O. analysis. Cluster energies obtained by the 6-31G* and 6-311++G(3df) basis sets show significant difference and the 6-311++G(3df) energies correlate better with bonding properties. The 6-31G* ground state is a cubic Be@Ge-8 that agrees with the literature. However, the 6-311++G(3df) ground state is a cube-distorted C-2v Be@Ge-8 with less cage strain. The Wade Mingos rule was added to explain this change. Conversion pathways from the lowest-energetic adsorptive exohedrons to the lowest-energetic endohedrons have been explored and the Mayer bond orders assisted to describe part of the conversion progress. (C) 2012 Elsevier B.V. All rights reserved.
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COMPUTATIONAL AND THEORETICAL CHEMISTRY 卷: 999 頁數: 154-161
