Re: line-id procedures question

On Thu, Oct 25, 2001 at 11:51 -0400, David P. Huenemoerder wrote:
> *** I propose that we add levels to the isis el_ion() function:  ***
> 
>      flag = el_ion ([proton_number_list], [ion_list],
>                     [lower_level_list], [upper_level_list]);


It might be better to add a trans() function (ie "transition")
with a similar interface and leave el_ion() as is.  Since the
level indices are currently very ion specific, perhaps 
the interface should take only a single ion?:

      flag = trans (Z, q, lower_levs, upper_levs);

where Z = proton number, q = ion charge. Either of the last 2 args
could be optional -- for example, if upper_levs were absent, that
would mean include all transitions going to the specified lower_levs.
If both were absent, that would mean include all transitions.
The latter case implies a close connection with the el_ion()
function except that 'trans' is restricted to take only a
single (Z,q) whereas el_ion() doesn't have that restriction.

> 
> or we add an explicit level-range functions analogous to wl() for
> wavelengths:
> 
>      flag = lv(lo_range, hi_range);
> 
> which might be useful if there are deterministic categories of levels,
> such as resonance, forbidden, intersystem, DR, (but I don't know if
> there is a code for the levels).

To filter categories of transitions, one might want something like

       trans_type ([types])

where 'types' is a list of type-codes, probably integers.
Maybe an actual usage would look something like

       trans_type ([DR_type, Res_type]);

However, I don't think such a type system is yet available.

 -- John

-- 
John C. Houck    MIT Center for Space Research
617-253-3849     One Hampshire St, NE80-6005, Cambridge, MA 02139
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