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Workspace Method abs_speciesSet

Description

Set up a list of absorption species tag groups.

Workspace variables like abs_species contain several tag
groups. Each tag group contains one or more tags. This method converts
descriptions of tag groups given in the keyword to the ARTS internal
representation (an ArrayOfArrayOfSpeciesTag). A tag group selects
spectral features which belong to the same species.

A tag is defined in terms of the name of the species, isotopologue, and a
range of frequencies. Species are named after the standard chemical
names, e.g., "O3". Isotopologues are given by the last digit of the atomic
weight, i.g., "O3-668" for the asymmetric ozone molecule including an
oxygen 18 atom. Groups of transitions are specified by giving a lower
and upper limit of a frequency range, e.g., "O3-666-500e9-501e9".

To turn on Zeeman calculation for a species, "-Z" may be appended
to its name: "O2-Z" or "O2-Z-66"

To turn on line mixing calculation for a species, "-LM" may be appended
to its name (or after the Zeeman tag): "O2-LM" or "O2-Z-LM-66"

The symbol "*" acts as a wild card. Furthermore, frequency range or
frequency range and isotopologue may be omitted.

Finally, instead of the isotopologue the special letter "nl" may be given,
e.g., "H2O-nl". This means that no absorption at all is associated
with this tag. (It is not quite clear if this feature is useful for
anything right now.)

Example:

   species = [ "O3-666-500e9-501e9, O3-686",
               "O3",
               "H2O-PWR98" ]

   The first tag group selects all O3-666 lines between 500 and
   501 GHz plus all O3-686 lines. 

   The second tag group selects all remaining O3 transitions.

   The third tag group selects H2O, with one of the complete
   absorption models (Rosenkranz 98). No spectrocopic line catalogue
   data will be used for that third tag group.

   Note that order of tag groups in the species list matters. In our
   example, changing the order of the first two tag group will give
   different results: as "O3" already selects all O3 transitions,
   no lines will remain to be selected by the
   "O3-666-500e9-501e9, O3-686" tag.

For CIA species the tag consists of the two involved species and
a dataset index. CIA species can be defined for multiple regions
The dataset index determines which region to use from the corresponding
CIARecord in abs_cia_data.

Example

species = [ "N2-CIA-N2-0, N2-CIA-N2-1" ]

For Hitran cross section species the tag consists of the species and
the tagtype HXSEC, e.g. CFC11-HXSEC. The data for the species must be
available in the hitran_xsec_data variable.
abs_xsec_agenda_checked and propmat_clearsky_agenda_checked
are set to be false.

Authors: Stefan Buehler

Synopsis

Variables