TY - JOUR
T1 - Energetics of transition-metal ions in low-coordination environments
AU - Zapata, S.
AU - Carlsson, A. E.
PY - 2002/12/1
Y1 - 2002/12/1
N2 - The energetics of the interaction of transition-metal ions with low-coordination, non-close-packed neighbor shells are studied by ab initio total-energy calculations using plane-wave and other basis sets. Total energies are calculated for small clusters containing 3d transition-metal ions in simple, low-coordination environments. The clusters are obtained by placing four molecules of NH3, H2O, or H2S at the vertices of a square or tetrahedron, with the N, O, or S facing the ion. The energy differences between square and tetrahedral structures are found to be ≈ 1 eV in several cases. Such a large magnitude is expected for open d-shell systems because of ligand-field-splitting effects, but similar energy differences are also found in closed-shell systems. We use the results to show that the main factors determining the structural energetics of the ions, in addition to direct ligand-ligand interactions, are the ligand-field splitting of the transition-metal d shell, and a contribution from the interaction of the ligand orbitals with the transition metal charge and sp orbitals. The results are used to parametrize a classical force field for Cu2+ and evaluate its accuracy.
AB - The energetics of the interaction of transition-metal ions with low-coordination, non-close-packed neighbor shells are studied by ab initio total-energy calculations using plane-wave and other basis sets. Total energies are calculated for small clusters containing 3d transition-metal ions in simple, low-coordination environments. The clusters are obtained by placing four molecules of NH3, H2O, or H2S at the vertices of a square or tetrahedron, with the N, O, or S facing the ion. The energy differences between square and tetrahedral structures are found to be ≈ 1 eV in several cases. Such a large magnitude is expected for open d-shell systems because of ligand-field-splitting effects, but similar energy differences are also found in closed-shell systems. We use the results to show that the main factors determining the structural energetics of the ions, in addition to direct ligand-ligand interactions, are the ligand-field splitting of the transition-metal d shell, and a contribution from the interaction of the ligand orbitals with the transition metal charge and sp orbitals. The results are used to parametrize a classical force field for Cu2+ and evaluate its accuracy.
UR - http://www.scopus.com/inward/record.url?scp=19244368193&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.66.224109
DO - 10.1103/PhysRevB.66.224109
M3 - Article
AN - SCOPUS:19244368193
SN - 0163-1829
VL - 66
SP - 2241091
EP - 2241098
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 22
M1 - 224109
ER -