method for generating and processing
of redundant internal coordinates
n≥ - 3, n≤ 3, n ≠ 0 (default: 3)
Values for the metric option:
- n = 1
- ``Delocalized Coordinates''
BmBt matrix is diagonalized for the complete set
of redundant internal coordinates, matrix
m is a unit
- n = -3
- Delocalized Coordinates obtained
with a modified matrix
m, the values of
can be defined by user input (see below).
- n = -1
- ``Hybrid Coordinates''
Natural internal coordinates are defined as in the old
iaut option. If a cage remains, delocalized coordinates
(as for n=1) are defined for the cage.
- n = -2
- Very simular to the n = 1 option,
but for the remaining cage delocalized coordinates with modified
m are defined as for n = - 3.
- n = 2
- ``Decoupled coordinates''
The redundant coordinates are divided into a sequence of blocks.
These are expected to have decreasing average force constants,
i.e. stretches, angle coordinates, torsions and
``weak'' coordinates. The
BBt matrix is
diagonalized for each block separately after the columns of
B were orthogonalized against the columns of
B of the the preceding blocks.
- n = 3
- ``Generalized natural coordinates''
Natural internal coordinates are defined first, for the
remaining cage decoupled coordinates are defined.