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Ab Initio Study of Inner Solvent Shell Reorganization in the Fe 2+ –Fe 3+ Aqueous Electron Exchange Reaction
Author(s) -
Jafri J. A.,
Logan J.,
Newton M. D.
Publication year - 1980
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.198000043
Subject(s) - chemistry , antibonding molecular orbital , valence (chemistry) , atomic orbital , molecular orbital , solvation shell , valence electron , basis set , ab initio , non bonding orbital , atomic physics , molecular orbital theory , crystallography , ion , computational chemistry , electron , molecule , solvation , density functional theory , physics , organic chemistry , quantum mechanics
Ab initio RHF molecular orbital calculations are carried out for several hydrate clusters of Fe 2+ and Fe 3+ , using a double‐zeta valence atomic orbital basis set and an effective core potential for inner shell electrons, and comparison is made with all‐electron results at the monohydrate level. The calculations are shown to give a good quantitiative account of the solvent shell radii and breathing vibration frequencies for the hexahydrates. The large decrease (∼0.15 Å) in going from Fe 2+ (H 2 O) 6 to Fe 3+ (H 2 O) 6 is related to the interaction of the a g (4 s ) and ϵ g (3 d ) Fe valence orbitals with the ligand 2 p ‐orbitals, with little π antibonding character found for the t g orbitals. The expansion of the 3 d orbitals in the Fe 2+ ion, relative to the Fe 3+ , is also noted and discussed in connection with the change in solvent shell size for the two complexes. The charge transfer from the ligands involves mainly a depletion of the hydrogen atom electrons, implying increased acidity for the first‐shell water molecules.