Communications in Theoretical Physics
Based on a theory model proposed for organic ferromagnets, the spin configuration and spin-wave excitations in quasi-one-dimensional organic polymer ferromagnets are studied. The results show that: 1) Owing to the unpaired electrons at side free-radicals, the degeneracy of the spin-wave will be removed, the lower branch of the spin wave excitations will split off into two branches, and it shows ferromagnetic characters; 2) The anisotropic interactions between the unpaired electrons at side free-radicals will make an energy gap appear between the ground state and the lowest excited state.
关键词:
molecules
Physica Status Solidi B-Basic Research
The electronic structure of the 13-atom Rh cluster is studied with the structure model optimized by Estiu and Zerner using the discrete variational local-spin density-functional method. The magnetic moment per atom of the cluster is calculated to be 0.54 mu(B), in good agreement with experimental measurements (0.48 +/- 0.13)mu(B). It confirms our previous assumption that the structural distortion of the Rh-13 cluster from a perfect icosahedron to its ground state geometry decreases its magnetic moment and makes the theoretical calculation close to the experimental measurement.
关键词:
molecules
Philosophical Magazine a-Physics of Condensed Matter Structure Defects and Mechanical Properties
The influence of the interstitial elements H, B, C, N and O on the bulk modulus and the theoretical strength of alpha-Ti was investigated using the discrete variational method under the local density approximation from first principles. The electronic structure and the total and binding energies were first evaluated with and without lattice relaxation and then used to assess the theoretical values of the bulk modulus and the theoretical strength under hydrostatic tension. It was shown that the binding energy was increased when H was in a solution of alpha-Ti but reduced when B, C, N or O was in solution. The bulk modulus and the theoretical strength were increased by C, O and N but reduced by H and B. A charge-density analysis showed that the bonds between Ti atoms were enhanced by the interstitial elements N, C and O but weakened, to some extent, by the incorporation of H.
关键词:
molecules
