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We revisit the well-known Mollwo-Ivey relation that describes the universal dependence of the absorption energies of F-type color centers on the lattice constant $a$ of the alkali-halide crystals, $E_{mbox{abs}}propto a^{-n}.$ We perform both state-of-the-art ab-initio Quantum Chemistry and post-DFT calculations of F-center absorption spectra. By tuning independently the lattice constant and the atomic species we show that the scaling of the lattice constant alone (keeping the elements fixed) would yield $n=2$ in agreement with the particle-in-the-box model. Keeping the lattice constant fixed and changing the atomic species enables us to quantify the ion-size effects which are shown to be responsible for the exponent $n approx 1.8$.
The anomalous plasmon linewidth dispersion (PLD) measured in K by vom Felde, Sprosser-Prou, and Fink (Phys. Rev. B 40, 10181 (1989)), has been attributed to strong dynamical electron-electron correlations. On the basis of ab initio response calculati
Favorable optoelectronic properties and ease of fabrication make NiO a promising hole transport layer for perovskite solar cells. To achieve maximum efficiency, the electronic levels of NiO need to be optimally aligned with those of the perovskite ab
Coherence and de-coherence are the most fundamental steps that follow the initial photo-excitation occurring in typical Pump&Probe experiments. Indeed, the initial external laser pulse transfers coherence to the system in terms of creation of multipl
The hyperfine interaction between the quadrupole moment of atomic nuclei and the electric field gradient (EFG) provides information on the electronic charge distribution close to a given atomic site. In ferroelectric materials, the loss of inversion
First-principles calculation predict that olivine Li4MnFeCoNiP4O16 has ferrotoroidic characteristic and ferrimagnetic configuration with magnetic moment of 1.56 muB per formula unit. The ferrotoroidicity of this material makes it a potential candidat