Nearest-neighbor coordination polyhedral clusters in metallic phases defined using Friedel oscillation and atomic dense packing

It is generally difficult to define coordination polyhedral clusters with multi-shelled nearest neighbors. The present work defines their cutoff distances in typical metallic phase structure types via Friedel oscillation and atomic dense packing. The nearest neighbors of a cluster are considered to be confined within the first effective Friedel minimum in the pair potential, with the radial distance ratio of the outermost shell to the innermost shell being r(L)/r(S) = 1.5. This ratio is further correlated to atomic radius ratio, facet-capping configuration and cluster coordination number after considering hard-sphere atomic dense packing. The cluster cutoff distance is obtained by multiplying the r(L)/r(S) ratio with the measured innermost shell distance, as is well validated in common cluster types.