Friday, June 29, 2018

resource recommendations - Where to find detailed measured emission spectra of all chemical elements?



I'd like to have something like this, but for single atoms and with more extended range of wavelengths.



All I could find e.g. for hydrogen was lots of talks about Rydberg formula etc. and plots of spectrum in visible region. But I need experimental data to look at, not something plotted from formulas like Rydberg's one.


Similarly for other elements, I mostly found only plots of spectral lines in visible range.


So, where can one find detailed measured spectra for all (or most) chemical elements, preferably with UV and IR parts? It'd be most useful to have it in numeric form (spreadsheet etc.) instead of pictures.



Answer



The NIST Atomic Spectra Database is a decent source for general-purpose lookup and identification of spectral transitions and levels. You will probably be more interested in their spectral line info. It also provides comprehensive references, both in a per-line basis (in the Line Ref column of the results to the Lines database) and via the bibliographic database query links at the top of the results pages.


The database also gives the relative intensities of the lines, as well as the transition lifetimes, in the form of the $A_{ki}$ of the lines results; for more information see here and here.


Regarding your comment:



Thanks for the reference. But while it's quite interesting, I'd still like to have raw spectroscopic measurement data, i.e. relative intensity as a function of wavelength, not result of processing it into a list of spectral lines.




The hard part of spectral measurements is the conversion of raw spectral data into a list of lines; the reverse direction (converting a line/strength list into a simulated spectrum) is easy, which is why the NIST database provides line lists, and not the raw experimental data. Also, the appearance of the raw data is highly dependent on the experimental conditions, whereas the lines/strengths is uniquely associated with each ion. You can simulate spectra from the line list if you know the ambient conditions (temperature, pressure).


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