Other Fits
Line Intensity Fitting
Line intensities can also be fit, which makes sense in three contexts:
- Where absolute intensities have been measured and a fit can
therefore determine the transition moment.
- Relative intensities have been measured of two or more bands, and
the relative transition moments are required.
- A series of relative intensity measurements have been made, and
the population distribution are required.
The essential procedure is the same as for line position fitting,
except that the line intensities replace the positions in the
observations file. When fitting, the Fit
type combo box should be set to "Intensity" rather than "Line", and you
will want to make sure that only parameters affecting the intensity are
floated. (In principle this will be all parameters, but you will
normally want to float the transition moments and temperature only.)
To fit populations set the required levels up as described in Non-Boltzmann Populations; this then provides
a parameter for each
level of interest in the manifold that can be floated as for other
parameters. Again you will normally want to float these population
parameters only.
Energy Level fits
This is essentially a special case of a line position fit. To force the
observed value in a given line in the input file to be treated as an
energy level, rather than a transition frequency, replace J S
and #
for the unwanted state with "-" and leave the manifold field blank. It
is also possible to force this for a complete file from the Log Window. If HITRAN or JPL line catalog files
are used as input, then these have energy level information in them and
selecting EUpper or ELower in the log window will cause the state
energy to be worked out (using the line position and lowers state
energy for EUpper). For other file formats the values given in the file
must be the energy level.
Procedures