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Small elemental clusters. I. The structures of Be 2 , Be 3 , Be 4 , and Be 5
Author(s) -
Whiteside Robert A.,
Krishnan Raghavachari,
Pople John A.,
KroghJespersen MaryBeth,
Von Ragúe Schleyer Paul,
Wenke Gottfried
Publication year - 1980
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.540010402
Subject(s) - binding energy , chemistry , electronic correlation , ab initio , beryllium , singlet state , perturbation theory (quantum mechanics) , atomic physics , equilateral triangle , crystallography , tetrahedron , computational chemistry , molecular physics , molecule , physics , excited state , quantum mechanics , geometry , mathematics , organic chemistry
The geometries and energies of beryllium clusters up to Be 5 are examined using ab initio molecular orbital theory. Allowances are made for electron correlation with Møller—Plesset perturbation theory to fourth order. Correlation is found to have a dramatic effect on the relative energies of the several structures examined for Be 4 and Be 5 . Furthermore, the effect of d ‐type basis functions on the correlation energy results in an increased binding energy for the clusters. Be 2 is only weakly bound. For Be 3 , the best estimate of the binding energy is 6 kcal/mole for the singlet equilateral triangle. Be 4 is tetrahedral in its ground state and the estimated binding is 56 kcal/mole. The best structure for Be 5 is a singlet trigonal bipyramid, and the binding energy is 88 kcal/mole at the highest level of theory used.