NIST Queries (astroquery.nist)

Tool to query the NIST Atomic Lines database (http://physics.nist.gov/cgi-bin/ASD/lines1.pl).

Getting started

This is a relatively simple module that you may use to query spectra from NIST. All the results are returned as a 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 Quantity object, for instance having units of nanometer, or angstrom or the like. For example, to use a lower wavelength value of 4000 Angstroms, you should use `4000 * u.AA` and if you want the same in nanometers, just use `400 * u.nm`. 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.AA, 7000 * u.AA, linename="H I")
>>> print(table)

    Observed        Ritz      Rel.     Aki     Acc. ...     Lower level         Upper level     Type   TP    Line
 ------------- ------------- ------ ---------- ---- ... ------------------- ------------------- ---- ----- --------
            -- 4102.85985516     --  4287700.0  AAA ...                  --                  --   --    --       --
            -- 4102.86191086     --   245010.0  AAA ... 2p     | 2P*  | 1/2 6s     | 2S   | 1/2   -- T8637       --
            --     4102.8632     --         --   -- ...            |      |            |      |   --    --      c57
 4102.86503481 4102.86503481     --         --   -- ... 2s     | 2S   | 1/2 6d     | 2D   | 5/2   E2    --   L11759
            -- 4102.86579134     --  2858300.0  AAA ...                  --                  --   --    --       --
 4102.86785074 4102.86785074     --         --   -- ... 2s     | 2S   | 1/2 6s     | 2S   | 1/2   M1    --   L11759
            -- 4102.86807252     --  2858400.0  AAA ...                  --                  --   --    --       --
      4102.892     4102.8991  70000   973200.0  AAA ...     2      |      |     6      |      |   -- T8637 L7436c29
            --     4102.8922     --         --   -- ...            |      |            |      |   --    --      c58
            -- 4102.92068748     --  5145000.0  AAA ... 2p     | 2P*  | 3/2 6d     | 2D   | 5/2   -- T8637       --
            --     4102.9208     --         --   -- ...            |      |            |      |   --    --      c59
            -- 4102.92144772     --   857480.0  AAA ...                  --                  --   --    --       --
            -- 4102.92350348     --   490060.0  AAA ... 2p     | 2P*  | 3/2 6s     | 2S   | 1/2   -- T8637       --
            --   4341.647191     --  7854800.0  AAA ... 2p     | 2P*  | 1/2 5d     | 2D   | 3/2   -- T8637       --
            --     4341.6512     --         --   -- ...            |      |            |      |   --    --      c60
           ...           ...    ...        ...  ... ...                 ...                 ...  ...   ...      ...
   6564.522552   6564.522555     -- 53877000.0  AAA ... 2p     | 2P*  | 1/2 3d     | 2D   | 3/2   -- T8637    L2752
            --      6564.527     --         --   -- ...            |      |            |      |   --    --      c67
            --      6564.535     --         --   -- ...            |      |            |      |   --    --      c68
   6564.537684   6564.537684     -- 22448000.0  AAA ... 2s     | 2S   | 1/2 3p     | 2P*  | 3/2   -- T8637 L6891c38
            --   6564.564672     --  2104600.0  AAA ... 2p     | 2P*  | 1/2 3s     | 2S   | 1/2   -- T8637       --
            --   6564.579878     --         --   -- ... 2s     | 2S   | 1/2 3s     | 2S   | 1/2   M1    --       --
            --      6564.583     --         --   -- ...            |      |            |      |   --    --      c66
   6564.584404   6564.584403     -- 22449000.0  AAA ... 2s     | 2S   | 1/2 3p     | 2P*  | 1/2   -- T8637 L6891c38
        6564.6      6564.632 500000 44101000.0  AAA ...     2      |      |     3      |      |   -- T8637 L7400c29
            --      6564.608     --         --   -- ...            |      |            |      |   --    --      c69
    6564.66464    6564.66466     -- 64651000.0  AAA ... 2p     | 2P*  | 3/2 3d     | 2D   | 5/2   -- T8637    L2752
            --     6564.6662     --         --   -- ...            |      |            |      |   --    --      c71
            --      6564.667     --         --   -- ...            |      |            |      |   --    --      c70
            --   6564.680232     -- 10775000.0  AAA ... 2p     | 2P*  | 3/2 3d     | 2D   | 3/2   -- T8637       --
            --   6564.722349     --  4209700.0  AAA ... 2p     | 2P*  | 3/2 3s     | 2S   | 1/2   -- T8637       --

Note that using a different unit will result in different output units in the Observed and Ritz columns.

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 ...                  --   --    --   --

Reference/API

astroquery.nist Package

Fetches line spectra from the NIST Atomic Spectra Database.

Classes

NistClass()
Conf Configuration parameters for astroquery.nist.