First-principles bond-length correlation for the omega structure of the 4d-transition elements

Using the full potential-linearised muffin tin orbitals (FP-LMTO) method,we have studied the shortest interatomic distance (SID) of the A1B(2) (C32) t ype-structure, so-called omega (Omega) phase, of Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd and Ag. it is shown that the SID in this phase correlates remarkably we ll with the single bond length D(1) given to these elements by Pauling's bo nd length (BL) versus bond number relation. The physical relevance of this result, which holds for stable and metastable Omega phases, lies in the ide ntification of the quantity D(1) which for metallic elements has long repre sented only a useful empirical parameter, to be used in the analysis and pr ediction of BLs, with a structural property that can be either directly mea sured, or accurately calculated by current ab initio methods. (C) 1999 Else vier Science S.A. All rights reserved.