Zusammenfassung
The correlation contribution to the cohesive energy of the Ar face-centered cubic (fcc) crystal has been evaluated within periodic and finite cluster models, using wave-function-based correlation techniques. The periodic local second-order Moller-Plesset perturbation (MP2) method is compared, in terms of accuracy and efficiency, to the incremental scheme employing standard MP2, local MP2, and ...
Zusammenfassung
The correlation contribution to the cohesive energy of the Ar face-centered cubic (fcc) crystal has been evaluated within periodic and finite cluster models, using wave-function-based correlation techniques. The periodic local second-order Moller-Plesset perturbation (MP2) method is compared, in terms of accuracy and efficiency, to the incremental scheme employing standard MP2, local MP2, and local coupled cluster [CCSD(T)] methods. Three different finite cluster models of increasing complexity have been used in the incremental calculations. The local MP2 treatment is found to be relatively insensitive to the choice of the cluster model, and it is shown that within the LMP2 treatment virtually identical results can be expected from the periodic and different incremental calculations. Moreover, the two approaches can be considered as complementary: The periodic treatment allows for a relatively inexpensive reference, while further improvement of the level of correlation treatment and the size of one-particle basis sets is achieved more easily within the incremental scheme.
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