Objects Mixture Species | <Prev Next> |

- Right-click on the species you are adding to in the tree view and select "Add new...", then select a linear, symmetric top or asymmetric top molecule
- Right click on a similar molecule entry (it must be of the
same type) and select "copy", then right click where you want
the new molecule to be and select paste.

The settings given here are common to all different types of mixture. Details of other settings are given in the sections for linear, symmetric top, asymmetric top and vibrating molecules.

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 species. |

Jmax | Maximum J to use in calculation - set to -1 (default) to use value from 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 in linear molecules an energy level will typically alternate between + and - parity with J (hence the e/f notation). |

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. |

Abundance |
Abundance of this isotopologue; default is 1 |

AssumedOrigin |
Assumed energy origin for Boltzmann
calculations; values > 1e50 (the default) imply an
automatic estimate of the lowest populated energy level in
the molecule. This can normally be left at the
default, except in unusual circumstances (most likely linear
molecules at very low temperatures) where it may be
necessary to set it manually to the energy of the lowest
level. It arises as the population, calculated as exp(-(E-AssumedOrigin)/kT))
can overflow when the estimated assumed origin is
significantly above the true lowest energy in the molecule.
Predicted intensities will otherwise be independent of the
value of the assumed origin unless the IntensityUnits
are set to Arbitrary or Squared. |