Spectra of Gas Discharges

Joachim Köppen Strasbourg/Illkirch/Kiel 2007

after the pages by John Talbot and using an enlarged version of his applet

Below are images of the spectra of the lines of each element which would be observed as emission lines in an electrical gas discharge. The images are screen shots of an applet - originally written by John Talbot - which reads in a file with wavelengths and intensities and makes a colourful representation of the spectrum. All data are taken from the NIST Atomic Spectra Databaseby the National Institute of Standards and Technology, Gaithersburg, MD., U.S.A. The line intensities are as given in these tables, to give an impression of the relative line strength. However, it must be emphasized that the spectra shown may not correspond to the discharges we see in the form of various street lamps, because the excitation conditions (electric voltage, temperature, density) may well be different ...

The Applet with user control of all parameters is here.

This is how the eyes of my students seem to perceive the colours of the solar continuum

and this is how they perceive the solar spectrum with its absorption lines

but this is how it looks to my own eyes

Click on any of the following spectra to show it in greater detail:





















The Applet with user control of all parameters is here.

The chemical elements
Element Symbol Data file Emission Lines
4000-7000 Å
1 Hydrogen H hydrogen.txt 5 JPEG
2 Helium He helium.txt 23 JPEG
6 Carbon C carbon.txt 27 JPEG
7 Nitrogen N nitrogen.txt 84 JPEG
8 Oxygen O oxygen.txt 73 JPEG
10 Neon Ne neon.txt 75 JPEG
11 Sodium Na sodium.txt 90 JPEG
12 Magnesium Mg magnesium.txt 54 JPEG
13 Aluminum Al aluminum.txt 38 JPEG
14 Silicon Si silicon.txt 109 JPEG
16 Sulfur S sulfur.txt 39 JPEG
18 Argon Ar argon.txt 159 JPEG
19 Potassium K potassium.txt XX JPEG
20 Calcium Ca calcium.txt 78 JPEG
26 Iron Fe iron.txt 235 JPEG
36 Krypton Kr krypton.txt 75 JPEG
XX Strontium Sr strontium.txt 72 JPEG
54 Xenon Xe xenon.txt 139 JPEG
XX Barium Ba barium.txt 116 JPEG
80 Mercury Hg mercury.txt 40 JPEG

Atomic Number The number of protons in the nucleus of the element.
Element Click on the name in this column to launch the Applet which displays an emission line spectrum of the corresponding element
Symbol Symbol from the table of the elements
Data File Click on the name to download a text file containing an a list of emission lines in Ångstroms and their associated strengths for the corresponding element
Emission Lines
4000-7000 Å
Number of tabulated emission lines in the visible wavelength range

All the data for these spectra are courtesy of the National Institute of Standards and Technology

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last update: 21 June 2007 J.Köppen