These are the settings for a molecule as a whole, i.e. those
common to all states (but
perhaps different for different isotopologues).
||Number of atoms. Only required if the l matrix is not being
used to calculate Franck-Condon factors, otherwise can be
left at zero.
||For linear point groups, this is taken as the maximum
vibrational angular momentum to include when simulating
||Colour - set to "None" to take value from elsewhere.
||Currently ignored for this
||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.
||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.
||Point group of molecule. Currently C1, Ci,
C2, Cs, D2, C2v,
C2h, D2h, Cinfinityv and Dinfinityh
||Number of vibrational modes to include in the calculation.
|Set false to hide vibrational
quantum numbers with vmin = vmax = 0
in all states. This is essential for large molecules with
||Abundance of this isotope; default is 1
||Can normally be left at the default value;
see the generic Molecule
entry for more information
||Threshold for discarding values. This
threshold is used to discard low frequency modes
(translations and rotations) and also values smaller than
this are set to zero in certain contexts to avoid spurious
mixing of modes or rotation of axis systems.