ISSN:
0192-8651
Keywords:
Chemistry
;
Theoretical, Physical and Computational Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Computer Science
Notes:
Two typical series of C60 embedded complexes (X@C60) (X = Li, Na, K, Rb, Cs; F, Cl, Br, I) have been chosen to study as prototypes, in which the Buckingham potential (exp-6-1) function was applied to calculating the interactions of the atom pairs. The potential parameters are obtained from related crystals by the simulations using molecular mechanics methods. To utilize the symmetry of the potential field in C60, the calculation is carried out along five typical radial directions. The computational results show that the interaction between the embedded atom and the C60 cage is not purely electrostatic. The repulsive energy, Erep, accounts for from 0.2% to 6.6% (for the alkali series), and from 1.5% to 58% (for the halogen series); the dispersive energy Edis accounts for from 1.2% to 6.5% (for the alkali series), and from 2.2% to 42% (for the halogen series); and the electrostatic energy, Ees, accounts for 99% to 87% (for the alkali series) and from 96% to 0% (for the halogen series) when the embedded atom is put at the center of the cage. Erep reaches up to 8% ∼ 35% (alkali), and 16% ∼ 704% (halogen); Edis up to 4% ∼ 16% (alkali) and 7% ∼ 26% (halogen); and Ees falls down to about 88% ∼ 49% (alkali), and 96% ∼ 0% (halogen), when the embedded atom deviates 1.8 A from the cage center. The total interactions, Einter, are all attractive for X (X = Li, Na, K, Rb, Cs; F. Cl, Br), but repulsive for the I atom. It is shown that the potential field in the C60 cage has nearly spherical symmetry in an area with a radius of 1.8 Å around the cage center. The same kinds of interactions for the atoms in the two individual series are compared, and some variation rules are obtained. For (Li@C60), the minimum energy equilibrium point deviates from the center by about 0.5 Å. © 1996 by John Wiley & Sons, Inc.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcc.4
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