NIST Queries (astroquery.nist)¶
Tool to query the NIST Atomic Lines database (https://physics.nist.gov/PhysRefData/ASD/lines_form.html).
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 Transition Rel. ... Type TP Line
------------- ------------- ------------- ------ ... ---- ----- --------
-- 4102.85985517 24373.2429403 -- ... -- T8637 --
-- 4102.86191087 24373.2307283 -- ... -- T8637 --
-- 4102.8632 24373.223 -- ... -- -- c57
4102.86503481 4102.86503481 24373.2121704 -- ... E2 -- L11759
-- 4102.86579132 24373.2076763 -- ... -- T8637 --
4102.86785074 4102.86785074 24373.1954423 -- ... M1 -- L11759
-- 4102.8680725 24373.1941249 -- ... -- T8637 --
4102.892 4102.8991 24373.05 70000 ... -- T8637 L7436c29
-- 4102.8922 24373.051 -- ... -- -- c58
-- 4102.92068748 24372.8815683 -- ... -- T8637 --
... ... ... ... ... ... ... ...
-- 6564.564672 15233.302588 -- ... -- T8637 --
-- 6564.579878 15233.267302 -- ... M1 -- --
-- 6564.583 15233.26 -- ... -- -- c66
6564.584404 6564.584403 15233.256799 -- ... -- T8637 L6891c38
6564.6 6564.632 15233.21 500000 ... -- T8637 L7400c29
-- 6564.608 15233.202 -- ... -- -- c69
6564.66464 6564.66466 15233.07061 -- ... -- T8637 L2752
-- 6564.6662 15233.067 -- ... -- -- c71
-- 6564.667 15233.065 -- ... -- -- c70
-- 6564.680232 15233.034432 -- ... -- T8637 --
-- 6564.722349 15232.9367 -- ... -- T8637 --
Length = 53 rows
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 Transition Rel. ... Upper level Type TP Line
-------- ----------- ----------- ----- ... ------------------- ---- ----- -----
-- 4020.871 2487.024 (200) ... 14 | | -- T8637 --
-- 4052.18664 2467.803411 -- ... 5d | 2D | 3/2 -- T8637 --
-- 4052.19376 2467.79907 -- ... 5p | 2P* | 3/2 -- T8637 --
-- 4052.22121 2467.78236 -- ... 5s | 2S | 1/2 -- T8637 --
-- 4052.23222 2467.77565 -- ... 5p | 2P* | 1/2 -- T8637 --
-- 4052.248747 2467.765585 -- ... 5f | 2F* | 5/2 -- T8637 --
-- 4052.24892 2467.765479 -- ... 5d | 2D | 5/2 -- T8637 --
-- 4052.26147 2467.75784 -- ... 5p | 2P* | 3/2 -- T8637 --
-- 4052.26174 2467.757676 -- ... 5d | 2D | 3/2 -- T8637 --
-- 4052.26738 2467.75424 -- ... 5g | 2G | 7/2 -- T8637 --
... ... ... ... ... ... ... ... ...
5128.65 5128.662 1949.83 (450) ... 10 | | -- T8637 L7452
-- 5169.282 1934.5047 -- ... 19 | | -- T8637 --
-- 5263.685 1899.8096 -- ... 18 | | -- T8637 --
-- 5379.776 1858.8134 -- ... 17 | | -- T8637 --
-- 5525.19 1809.8925 (150) ... 16 | | -- T8637 --
-- 5711.464 1750.8646 (180) ... 15 | | -- T8637 --
-- 5908.22 1692.5572 (540) ... 9 | | -- T8637 --
-- 5956.845 1678.7409 (210) ... 14 | | -- T8637 --
-- 6291.918 1589.3405 (250) ... 13 | | -- T8637 --
-- 6771.993 1476.6701 (300) ... 12 | | -- T8637 --
-- 6946.756 1439.5208 -- ... 20 | | -- T8637 --
Length = 37 rows
Reference/API¶
astroquery.nist Package¶
Fetches line spectra from the NIST Atomic Spectra Database.
Classes¶
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Configuration parameters for |