- Stage 1: Solve secular determinant for single phase
shift in AO Basis
- MOs occur in degenerate pairs: 2(α + 1.414β)
and 2(α - 1.414β);
there are two equally probable positions for the node in
the cycle, placing the
node (phase shift) in the AO basis at precisely one or other
of the two intersections of the C2 axis with the
cycle.
- The degeneracies are only true for a cycle of zero
width/height. For a cycle of finite
(differing) width/height, one node
would lie along the axis, the other would be
perpendicular to the axis, the compression and
hence energy of each being clearly different.
© H. S. Rzepa, 2006-7.