0000000000894245
AUTHOR
K. M. Hasselbach
Mössbauer effect study of the electronic ground state of iron(II)in tris(2-chlorophenanthroline)iron(II) perchlorate
Abstract Mossbauer spectra of [Fe(2-Cl-phen) 3 ](ClO 4 ) 2 ·H 2 O have been measured in the temperature range 293 − 5 K. The spectra indicate that the iron atom in this compound possesses a spin quintet ground state throughout the temperature range under study, in contradiction to the suggested high spin-low spin transition, which has been concluded from a magnetic susceptibility study by other authors. From a theoretical analysis of the temperature dependence of the quadrupole splitting, with trigonal distortion, spin-orbit coupling, and effects of covalency taken into account, the ground term of iron(II) in this compound has been elucidated as being 5 A 1 ( 5 T 2g ), separated from the 5 …
EXTENDED HÜCKEL MOLECULAR ORBITAL CALCULATION OF THE TEMPERATURE DEPENDENCE OF THE QUADRUPOLE SPLITTING OF [Fe(H2O)6] SiF6 AND KFeCl3
A number of papers have appeared in which the temperature dependence of the quadrupole splitting has been treated, whereby covalency effects have been considered by introducing the orbital reduction factor k, with k ranging from 1.-0.7. There are, however, two problems : (1) k is unisotropic if the symmetry is lower than cubic, (2) the spin orbit coupling of the ligand electrons are usually neglected. These two problems have been treated here by using SCCEHMO [1] calculations on two examples, [Fe(H2O)6]SiF6 and KFeCl3, which have been previously delt with by other authors using ligand field theory [2, 3]. For both compounds the differences between the measured and the calculated quadrupole …