Molecule Types Linear Molecules | <Prev Next> |

nNuclei | Number of nuclei to calculate hyperfine structure for. Leave this at 0 unless you want the hyperfine structure simulated. |

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.
For linear molecules a given energy level will typically
alternate between + and - parity with J (hence the e/f notation). Note that
this should be set to False
if simulating hyperfine structure as otherwise confusing
results can be obtained. |

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. |

Symmetric | Set true if the molecule has a centre of symmetry, and g
or u must be specified for individual states. |

SymWt | Statistical weight of symmetric rotational levels, or all
levels if no centre of symmetry. See Making
a linear molecule data file for how to set this up if
there is a centre of symmetry. Note that any nucleus for
which hyperfine structure is to be calculated should not be
included in calculating the statistical weights - see under the linear nucleus settings for
notes on the required calculation. If there is no centre of symmetry this can be left at 1, unless nuclear spin states are required in the partition function. Versions of PGOPHER before 8.0.217 forced this, and loading old data files will set SymWt to 1. |

AsymWt | Statistical weight of asymmetric rotational levels.
Ignored if no centre of symmetry. |

RSquaredH | Set to use the R^{2}
Hamiltonian rather than the default N^{2} form. |

ShowJ | Show J in state label. |

ShowOmega | Show Omega in state label. |

ShowN | Show N in state label. |

ShowFNumber | Show F Number in state label. |

Showef | Show e/f symmetry in state label. |

Abundance | Abundance of this isotope; 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 at
very low temperatures) where it may be necessary to set it
manually to the energy of the lowest level. It arises when
the population, calculated as exp(-(E-AssumedOrigin)/kT)),
overflows 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.For linear molecules the lowest energy in any given state is estimated by taking the lowest value of: which typically differ from the actual lowest energy by ~ B. |