A previous automatic fitting procedure of EPR spectra has been extended with the purpose to characterise coupled paramagnetic complexes in powders and frozen solutions. The theoretical EPR spectra ...were obtained by matrix diagonalization of a general spin Hamiltonian. A least-squares fitting procedure using analytical derivatives of the calculated spectrum with respect to the spectroscopic, fine structure, nuclear quadrupole, electron–electron, and hyperfine coupling tensors was used to refine those parameters. The powder spectra of matrix isolated
CF
3 and RCF
2CF
2
radicals, previously measured at low temperature, were reanalysed with this method. A theoretically modeled complex consisting of a Cu
2+ ion, featuring an axially symmetric g-tensor and
63Cu hyperfine structure anisotropy, and a free radical located at different orientations, with respect to the symmetry axis of the Cu
2+ ion, was examined in order to investigate the possibility to recover the magnetic parameters of the separate units and the magnetic couplings between them.
We present a theoretical investigation, based on ab-initio Hartree–Fock (HF) and density functional theory (DFT) methods and Cu
7 cluster models, of the adsorption of alkali metals (Li, Na and K) on ...a (111) copper surface. Results show that both methods agree, in that lithium adsorbs on a three-fold hollow site and potassium is adsorbed on a top site. For sodium the calculations differ: DFT leads to adsorption on a top site whereas HF calculations predicts adsorption on a three-fold site. Local specific interactions responsible for the stabilization of the alkalis on the different adsorption sites are identified and discussed in the framework of DFT. On the other hand, starting from a simple analytic function representing pairwise interactions, we present a procedure to obtain the surface corrugations, obtaining good descriptions of its characteristic features such symmetry, position of the minima, and saddle points.
In this paper we investigate the variation, along the periodic table, of 2s‐core ionization energies, using both relativistic and non‐relativistic calculations. We show that electron relaxation ...energies display variations typical of the shell‐filling process, while their relativistic contributions show specifically distorted shell features. Just as for the 1s‐core ionization energies, investigated earlier, the sensitivity of these differential properties to the shell‐filling process may be used as a probe of the accuracy of calculations of core ionization energies. Discrepancies with experimental results are critically analyzed.
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