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Symmetry

 

AOMX works with a basis of Slater determinants. The advantage is a complete independence of the molecular symmetry of the investigated molecule. On he other hand, the lacking of symmetry blocking in the Hamiltonian matrix means that computational effort will be relatively high and that the symmetry of the calculated eigenstates is not known for the present. The numerical effort in calculations without spin-orbit coupling will be reduced, however, by taking advantage of the tex2html_wrap_inline1747 blocking of the Hamiltonian matrix which is still present with Slater determinants. In addition, information about spin multiplicity will be gained. AOMX can make available the complete information about term symbols, which is known to be implicitly containded in the eigenvectors, for the effective rotational symmetries tex2html_wrap_inline1749 (cubic), tex2html_wrap_inline1751 (tetragonal), tex2html_wrap_inline1753 (trigonal), tex2html_wrap_inline1755 (orthorhombic) and tex2html_wrap_inline1757 (monoclinic) as well as the corresponding double groups.gif gif The terminus effective rotational group here means rotational group of the holoedrized point group of the complexgif - all more or less frequently occuring symmetries can be reduced to one of the point groups mentioned above. For this purpose, AOMX determines characters with respect to representative symmetry operations from the eigenvectors: in cubic symmetry these are the rotations tex2html_wrap_inline1759 and tex2html_wrap_inline1761 , in case of tetragonal symmetry tex2html_wrap_inline1763 and tex2html_wrap_inline1765 , in the trigonal case tex2html_wrap_inline1767 (simple group) resp. tex2html_wrap_inline1761 (double group), in orthorhombic symmetry tex2html_wrap_inline1765 and tex2html_wrap_inline1761 , in the monoclinic case it is tex2html_wrap_inline1765 . This must be kept in mind when coordinates are supplied since determination of characters will be successful only if the symmetry elements of the input geometry coincide with those mentioned above.



Heribert Adamsky
Sat Sep 14 16:23:16 MET DST 1996