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Spin Population Analysis


The population analysis techniques described in Section gif may also be used in combination with spin dependent DFT to investigate the distribution of electronic spin within a system. In order to achieve this, the spin up and spin down electronic populations are analysed separately and their sums and differences yield the charges and net spins respectively. This approach must be used because if any states within the system are independent of spin this will yield an ill-conditioned matrix of overlaps between the projected states tex2html_wrap_inline2952 and attempting to invert this matrix will cause numerical problems (See Appendix gif).

This section demonstrates the use of spin population analysis techniques in molecular and bulk systems. Subsection gif examines the results for three diatomic molecules, including tex2html_wrap_inline2954 which is paramagnetic. The results for ferromagnetic and antiferromagnetic crystals are compared in Subsection gif.

Matthew Segall
Wed Sep 24 12:24:18 BST 1997