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- Jansson, Per-Olof, 1948-
(author)
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Reduction of finite-group representations and influence of lattice symmetry on some properties in condensed-matter physics
- 1984
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Doctoral thesis (other academic/artistic)abstract
- The first part of this thesis describes a method for calculating irreducible matrix representatives of arbitrary finite groups. Using a projection operator technique, a problem of degeneracy in the eigenvalues appear. By using a linear combination of irreducible group representatives the degeneracy is shown to be removed. The second part uses the knowledge of the irreducible representatives of the group of the Hamiltonian for symmetry adaptation of crystal spin-orbitals. Two methods are described; one applicable to the LCAO-method and the other one to plane wave-methods. The third part is a theoretical study in the effect of a rare gas matrix on the transition energies of SiO; especially the A-X and E-X transitions. It is shown how the equilibrium distances are contracted at an increasing rate in the series X-A-E. Accurate dipole moments and dipole polarizabilities are calculated for the different states considered. In the last part it is shown that there is no obvious connection between a high concentration of a certain type of resistor in a random resistor network and a high power dissipation; a 'hot spot'.
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