nNuclei 
Number of nuclei to calculate hyperfine structure for.
Leave this at 0 unless you want the hyperfine structure
resolved. 
Jmin 
Minimum J to use in calculation  set to 1 (default) to
use value from the species. 
Jmax 
Maximum J to use in calculation  set to 1 (default) to
use value from the species. 
Colour 
Colour  set to "None" to take value from elsewhere as
explained in Determining Colours
and J ranges. 
JAdjustSym 
If set, energy level plots
and Fortrat diagrams will take account of the alternation in
symmetry with J
that is often found. For example the E+ and E Wang matrices
will alternate in J
for selected point groups  see Axis
systems and symmetries for asymmetric tops for more
details.

BlockMatrix 
Set to force check of
Hamiltonian matrix for factorization into blocks before
diagonalization. If blocks are found, these are diagonalized
separately, ensuring states that have no connecting matrix
elements are not accidentally mixed if the eigenvalues
happen to be very close. In principle, if full use is made
of symmetry and states are separated into separate manifolds
as appropriate, this should not be necessary but can easily
happen if selected terms in the Hamiltonian are zero or
interactions between states are omitted.

AbsoluteE 
True if energies have not been offset. This
is not the default for compatibility with previous versions,
though perhaps should be for new calculations. Setting this
false (the default) allows transitions with negative
frequencies, which can occasionally be convenient for
simulations involving a small spread of frequencies around a
large central frequency where a large offset is applied to
the upper state origin. This can give erroneous negative
frequencies; while there is logic to detect common cases
where this might arise, some calculations (typically
involving near degenerate manifolds) require this to be set
to true for correct operation.

PointGroup 
Point group  C_{1}, C_{i}, C_{2},
C_{s}, D_{2}, C_{2v}, C_{2h}
or D_{2h} 
Representation 
Representation  Ir, IIr, IIIr, Il, IIl or IIIl 
SReduction 
Use Watson's S reduction (as opposed to A). 
eeWt 
Statistical weight for ee levels for totally symmetric
vibronic states. The weights will be permuted appropriately
for vibronic states of other symmetries. Note that any
nucleus for which hyperfine structure is to be calculated
should not be included in calculating the statistical weights
 see under the nucleus
settings for notes on the required calculation. 
eoWt 
Statistical weight for eo levels for totally symmetric
vibronic states. 
oeWt 
Statistical weight for oe levels for totally symmetric
vibronic states. 
ooWt 
Statistical weight for oo levels for totally symmetric
vibronic states. 
C2zAxis 
a, b, or c; C_{2} axis in C_{2v}, C_{2}
or C_{2h}; axis perpendicular to symmetry plane in C_{s}
 see Axis systems and symmetries for
asymmetric tops

C2xAxis 
a, b, or c; typically the out of plane axis in C_{2v},
but either of the two axes that are not the C_{2}
axis can be chosen, and both possibilities are common in the
literature. See Axis systems and
symmetries for asymmetric tops for more discussion.

PseudoC2v 
Ignore any operators breaking C_{2v} symmetry 
see Pseudo C2v Symmetry

FakeSym 
Turn off transition moment test  see the discussion in Pseudo C2v Symmetry 
PhaseAdjust 
Multiply the basis states by
a phase factor chosen to reduce the number of imaginary
matrix elements. The factors are:

K even, +

K even, 

K odd, +

K odd, 

N even

1

i

i

1

N odd

i

1

1

i

See the description of the basis states
used. 
SingleSubBasis 
Set true to use a single subbasis for a
given state, rather than splitting E+/E/O+/O Wang
symmetries. For lower symmetry molecules, where the Wang
symmetries are mixed, this can produce different assignments
of the K_{a} and K_{c}
quantum numbers, and for a single state will force the
standard asymmetric top energy order, provided BlockMatrix is false.
