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An insight into optical and EPR properties of AgCl and AgF complexes through MS–Xα and SCCEH calculations
Authors:R Valiente  J A Aramburu  M T Barriuso  M Moreno
Abstract:MS-Xα and SCCEH calculations on the Ag2+ complexes AgFurn:x-wiley:00207608:media:QUA560520430:tex2gif-stack-5 and AgClurn:x-wiley:00207608:media:QUA560520430:tex2gif-stack-6 (displaying an elongated D4h symmetry) have been carried out for a better understanding of their experimental optical and EPR properties. As salient features, the present work supports that the unpaired electron in AgClurn:x-wiley:00207608:media:QUA560520430:tex2gif-stack-7 spends a little more time on ligands than on Ag2+, in agreement with the previous analysis of EPR and optical data for KCl:Ag2+. Furthermore, the five experimental optical transitions observed in that case are reasonably assigned. The first transition (observed at 12,500 cm?1) is assigned to a jump involving the 5a1g orbital built mainly (∽70%) from 3p orbitals of axial ligands, a fact that reflects the distinct level scheme for AgClurn:x-wiley:00207608:media:QUA560520430:tex2gif-stack-8 when compared to that for more ionic complexes. Calculations on AgFurn:x-wiley:00207608:media:QUA560520430:tex2gif-stack-9 and AgFurn:x-wiley:00207608:media:QUA560520430:tex2gif-stack-10 performed as a function of the equatorial Ag2+ –F? distance led to a reasonable understanding of experimental gyromagnetic and superhyperfine tensors displayed by Ag2+ in fluorides. The different relative decrease undergone by g‖– go (8%) and g ? – go (28%) on passing from CsCdF3:Ag2+ to RbCdF3:Ag2+ is shown to be consistent with the formation of AgFurn:x-wiley:00207608:media:QUA560520430:tex2gif-stack-11 and AgFurn:x-wiley:00207608:media:QUA560520430:tex2gif-stack-12 complexes, respectively, related to the different substitutional position of Ag2+ in such lattices. The decrement of about 8.5% experienced by both g‖ – go and g? – go values on going from CsCdF3:Ag2+ to NaF:Ag2+ is pointed out to reflect the different electrostatic potential (exerted by the rest of the lattice upon the complex) seen by AgFurn:x-wiley:00207608:media:QUA560520430:tex2gif-stack-13 embedded in NaCl or perovskite-type lattices. © 1994 John Wiley & Sons, Inc.
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