Jahn–Teller coupling and the influence of strain in Tg and Eg ground and excited states – A ligand field and DFT study on halide MIIIX6 model complexes [M=TiIII–CuIII; X=F−, Cl−]

The effect of electron cloud expansion on the red luminescence of Sr4Al14O25:Mn4+ revealed by calculation of the Racah parameters

“…When an atom has more than one electron there will be certain electrostatic repulsion between those electrons, and the amount of repulsion depends on the number and the spin of electrons and the orbitals they occupy [16][17][18][19]. The total repulsion is expressed in terms of three parameters A, B and C, known as the Racah parameters after Giulio Racah, who first described them [16][17][18][19]. The nephelauxetic effect, originating from the Greek known for cloud-expanding, refers to a decrease in the Racah interelectronic repulsion parameter, given the symbol B and C, which occurs when a transition metal free ion forms a complex with ligands [16][17][18][19].…”

“…Besides the thermal vibration caused by the temperature, the spectral configuration is finally determined by the electronic effect and electro-magnetic interaction of the activator suffering from a certain crystal circumstance, depending on the symmetry of crystal site. When an atom has more than one electron there will be certain electrostatic repulsion between those electrons, and the amount of repulsion depends on the number and the spin of electrons and the orbitals they occupy [16][17][18][19]. The total repulsion is expressed in terms of three parameters A, B and C, known as the Racah parameters after Giulio Racah, who first described them [16][17][18][19].…”

Density functional theory study of the multimode Jahn‐Teller problem in the fullerene anion

“…[23][24][25][26][27][28][29] In short, it is necessary to know the geometries and the energies of the HS and LS nuclear configuration. For the case of the LS conformation, since the system is in a nondegenerate electronic ground state, the geometry, as well as the corresponding energy, is obtained by standard DFT, whereas for the HS conformation the electronic state must be represented by more than one Slater Determinant, in this case by three.…”

“…[21] Furthermore, experimentally observed distorted structure of fullerene anion may appear in different low symmetry (LS) point groups depending on the environment. [22] In this study, the results obtained by multideterminantal density functional theory (MDDFT) [23][24][25][26][27][28] for the distortion of C À 60 ion, for the epikernel subgroups of the I h point group as well as their further distortion to C 2h is presented. To tackle the multimode problem, the intrinsic distortion path (IDP) analysis [23c,24b] in which the distortion is represented as a superposition of all totally symmetric normal modes in the LS point groups, has been performed.…”

Density Functional Theory Study of the Multimode Jahn-Teller Effect – Ground State Distortion of Benzene Cation

“…KS-DFT in its present implementations is not able to derive correct energies in the case of orbital degeneracy [3,9,10]. On the other hand, multideterminental-DFT approach, developed by Daul et al [11,12], can be successfully applied for detailed analysis of the JT active molecules [10][11][12][13][14][15][16][17][18][19][20]. This method gives the JT parameters, Fig.…”