Tool to query the NIST Atomic Lines database (http://physics.nist.gov/cgi-bin/ASD/lines1.pl).
This is a relatively simple module that you may use to query spectra from NIST. All the results are returned as an astropy.table.Table. To do this you just need to specify the lower and the upper wavelength for the spectrum you want to fetch. These wavelengths must be specified as an appropriate astropy.units Quantity object, for instance having units of nanometer, or angstrom or the like. Of course there are several optional parameters you can also specify. For instance use the linename parameter to specify the spectrum you wish to fetch. By default this is set to “H I”, but you can set it to several other values like “Na;Mg”, etc. Lets now see a simple example.
>>> from astroquery.nist import Nist
>>> import astropy.units as u
>>> table = Nist.query(4000 * u.nm, 7000 * u.nm, linename="H I")
>>> print(table)
Observed Ritz Rel. Aki ... Upper level Type TP Line
-------- ----------- ----- --------- ... ------------------- ---- ----- ----
-- 4020.871 (200) 5526.5 ... -- -- -- --
-- 4052.18664 -- 1238100.0 ... 5d | 2D | 3/2 -- T8637 --
-- 4052.19376 -- 737160.0 ... 5p | 2P* | 3/2 -- T8637 --
-- 4052.22121 -- 215030.0 ... -- -- -- --
-- 4052.23222 -- 737210.0 ... 5p | 2P* | 1/2 -- T8637 --
-- 4052.248747 -- 2412100.0 ... -- -- -- --
-- 4052.24892 -- 1485800.0 ... -- -- -- --
-- 4052.26147 -- 18846.0 ... 5p | 2P* | 3/2 -- T8637 --
... ... ... ... ... ... ... ... ...
-- 5525.19 (150) 2470.9 ... -- -- -- --
-- 5711.464 (180) 3515.8 ... -- -- -- --
-- 5908.22 (540) 70652.0 ... 9 | | -- T8637 --
-- 5956.845 (210) 5156.2 ... -- -- -- --
-- 6291.918 (250) 7845.7 ... -- -- -- --
-- 6771.993 (300) 12503.0 ... 12 | | -- T8637 --
-- 6946.756 -- 688.58 ... -- -- -- --
There are several other optional parameters that you may also set. For instance you may set the energy_level_unit to any one of these values.
'R' 'Rydberg' 'rydberg' 'cm' 'cm-1' 'EV' 'eV' 'electronvolt' 'ev' 'invcm'
Similarly you can set the output_order to any one of ‘wavelength’ or ‘multiplet’. A final parameter you may also set is the wavelength_type to one of ‘vacuum’ or ‘vac+air’. Here is an example with all these parameters.
>>> from astroquery.nist import Nist
>>> table = Nist.query(4000 * u.nm, 7000 * u.nm, 'H I',
... energy_level_unit='eV', output_order='wavelength',
... wavelength_type='vacuum')
>>> print(table)
Observed Ritz Rel. Aki ... Upper level Type TP Line
-------- ----------- ----- --------- ... ------------------- ---- ----- ----
-- 4020.871 (200) 5526.5 ... -- -- -- --
-- 4052.18664 -- 1238100.0 ... 5d | 2D | 3/2 -- T8637 --
-- 4052.19376 -- 737160.0 ... 5p | 2P* | 3/2 -- T8637 --
-- 4052.22121 -- 215030.0 ... -- -- -- --
-- 4052.23222 -- 737210.0 ... 5p | 2P* | 1/2 -- T8637 --
-- 4052.248747 -- 2412100.0 ... -- -- -- --
-- 4052.24892 -- 1485800.0 ... -- -- -- --
-- 4052.26147 -- 18846.0 ... 5p | 2P* | 3/2 -- T8637 --
... ... ... ... ... ... ... ... ...
-- 5525.19 (150) 2470.9 ... -- -- -- --
-- 5711.464 (180) 3515.8 ... -- -- -- --
-- 5908.22 (540) 70652.0 ... 9 | | -- T8637 --
-- 5956.845 (210) 5156.2 ... -- -- -- --
-- 6291.918 (250) 7845.7 ... -- -- -- --
-- 6771.993 (300) 12503.0 ... 12 | | -- T8637 --
-- 6946.756 -- 688.58 ... -- -- -- --