Electrostatic Interaction of dⁿ Systems in Tetragonal Fields

Abstract

Energy levels of nd transition metal ions in a ligand field of the tetragonal symmetry are studied in the strong field approximation. In this field, d level is split into four sub-levels differing in energy, of symmetry b₁, a₁, e and b₂ respectively. Starting from the configurations containing these orbitals, Coulomb interaction between electrons is introduced, which gives rise to energy levels, each characterized by SΓ. Matrix elements of Coulomb interaction are expressed in terms of Racah’s parameters A, B and C with the ligand field parameters X, Y and Z which give the intervals between orbital energies. These matrix elements are shown for d², d³, d⁴ and d⁵.