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Crystal Field in Rare‐Earth Complexes: From Electrostatics to Bonding
Author(s) -
Alessandri Riccardo,
Zulfikri Habiburrahman,
Autschbach Jochen,
Bolvin Hélène
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201705748
Subject(s) - ionic bonding , electrostatics , atomic orbital , crystal field theory , crystal (programming language) , chemistry , covalent bond , crystallography , ab initio , field (mathematics) , computational chemistry , chemical physics , electron , physics , ion , quantum mechanics , mathematics , organic chemistry , computer science , pure mathematics , programming language
The flexibility of first‐principles (ab initio) calculations with the SO‐CASSCF (complete active space self‐consistent field theory with a treatment of the spin‐orbit (SO) coupling by state interaction) method is used to quantify the electrostatic and covalent contributions to crystal field parameters. Two types of systems are chosen for illustration: 1) The ionic and experimentally well‐characterized PrCl 3 crystal; this study permits a revisitation of the partition of contributions proposed in the early days of crystal field theory; and 2) a series of sandwich molecules [Ln(η n ‐C n H n ) 2 ] q , with Ln=Dy, Ho, Er, and Tm and n =5, 6, and 8, in which the interaction between Ln III and the aromatic ligands is more difficult to describe within an electrostatic approach. It is shown that a model with three layers of charges reproduces the electrostatic field generated by the ligands and that the covalency plays a qualitative role. The one‐electron character of crystal field theory is discussed and shown to be valuable, although it is not completely quantitative. This permits a reduction of the many‐electron problem to a discussion of the energy of the seven 4f orbitals.