PI
The normal density matrix is composed of atomic orbitals, that is s,
px, py and pz. PI allows the user to see how each atom-atom interaction
is split into s, p,
and d
bonds. The
resulting "density matrix" is
composed of the following basis-functions: s-s,
p-s, p-p, d-s,
d-p, d-d.
The on-diagonal terms give the hybridization
state, so that an sp2 hybridized system would be represented as
s-s:
1.0, p-s:
2.0, p-p:
1.0.