Atomic Spectra

Neon spectrum

Argon Hydrogen Helium Iodine Nitrogen Neon Mercury Sodium

This is an attempt to give a reasonable accurate picture of the appearance of the neon spectrum, but both the images are composite images. The image below is composed of segments of three photographs to make the yellow and green lines more visible along with the much brighter red lines. Then the image below was reduced and superimposed on the image above, because with the exposure reasonable for the bright tube, only the red lines were visible on the photograph.

Some of the visible lines of neon: l nm Color 540.1 green 585.2 yellow 588.2 yellow 603.0 orange 607.4 orange 616.4 orange 621.7 red-orange 626.6 red-orange 633.4 red 638.3 red 640.2 red 650.6 red 659.9 red 692.9 red 703.2 red

This is a section of the sign shown below, which has a central neon section and another gas mixture producing blue light around it. Such signs are excited by voltages of a few thousand volts produced by a transformer that raises the voltage of the ordinary AC line voltage.

Atomic Spectra

Mercury spectrum

Argon Hydrogen Helium Iodine Nitrogen Neon Mercury Sodium

At left is a mercury spectral tube excited by means of a 5000 volt transformer. At the right of the image are the spectral lines through a 600 line/mm diffraction grating. The prominent mercury lines are at 435.835 nm (blue), 546.074 nm (green), and a pair at 576.959 nm and 579.065 nm (yellow-orange). There are two other blue lines at 404.656 nm and 407.781 nm and a weak line at 491.604 nm.