EMPIRICAL POTENTIAL-ENERGY FUNCTION FOR CALCIUM SOLIDS AND CLUSTERS

Citation
Km. Andersson et al., EMPIRICAL POTENTIAL-ENERGY FUNCTION FOR CALCIUM SOLIDS AND CLUSTERS, Physical review. B, Condensed matter, 49(5), 1994, pp. 3089-3097
Citations number
45
Categorie Soggetti
Physics, Condensed Matter
ISSN journal
01631829
Volume
49
Issue
5
Year of publication
1994
Pages
3089 - 3097
Database
ISI
SICI code
0163-1829(1994)49:5<3089:EPFFCS>2.0.ZU;2-I
Abstract
An empirical potential-energy function, consisting of two- and three-b ody terms, has been derived for the study of calcium solids and cluste rs. With a single set of parameters, this potential reproduces the pho non frequencies and elastic constants of both the low-temperature fee and the high-temperature bcc crystalline phases to a high degree of ac curacy. It also gives a sensible energy profile for the tetragonal (Ba in path) interconversion of the two structures, which are both minima along the path. The potential predicts that the fee and hcp solids hav e almost equal cohesive energies, with that of the bcc phase being 0.0 2 eV lower. Other cubic phases and various two-dimensional and one-dim ensional structures have lower cohesive energies. The potential leads to the conclusion that the most stable clusters tend to be polytetrahe dral, leading to icosahedral packing, thereby maximizing coordination number.