8.13-14 | Fall 2016 | Undergraduate

Experimental Physics I & II "Junior Lab"


Optical Emission Spectra of Hydrogenic Atoms


Optical Emission Spectra experiment equipment.

This experiment is an exercise in optical spectroscopy and a study of the spectra of hydrogenic atoms: atoms with one “optical” electron outside a closed shell of other electrons. A high-resolution scanning monochromator is used to study the Balmer lines of hydrogen and the more complex hydrogenic spectrum of sodium, using the mercury spectrum as the wavelength calibrator. The measured Balmer wavelengths are compared with the wavelengths predicted by the quantum theory of the hydrogen spectrum, and a value of the Rydberg is derived. The transitions responsible for the sodium spectrum are identified, and regularities in the fine structure and adherence to selection rules are observed. A measurement of the isotope shift between the Balmer lines of hydrogen and deuterium is made from which the ratio of the deuteron mass to the proton mass is derived.

Lab Guide

Optical Emission Spectra of Hydrogenic Atoms Lab Guide (PDF)


Bohr, Niels. Nobel Prize Lecture, “The Structure of the Atom.” (1922).

Lamb, Willis E. Nobel Prize Lecture, “Fine Structure of the Hydrogen Atom.” (1955).

White, Harvey E. “Hydrogen Fine Structure and the Dirac Electron.” In Introduction to Atomic Spectra. 1st ed. New York, NY: McGraw-Hill, 1934, pp. 132-138. ISBN: 9780070697201.

Richtmyer, F. K., E. H. Kennard, and T. Lauritsen. “Multiplet Levels for One-electron Atoms.” In Introduction to Modern Physics. 5th ed. New York, NY: McGraw-Hill, 1955, pp. 258-266.

Eisberg, Robert M., and Robert Resnick. “Spin-Orbit Interaction Energy and the Hydrogen Energy Levels.” In Quantum Physics of Atoms, Molecules, Solids, Nuclei, and Particles. New York, NY: Wiley, 1974, pp. 284-295. ISBN: 9780471234647.

Hansch, Theodor W., Arthur L. Schawlow, and George W. Series. “The Spectrum of Atomic Hydrogen.” Scientific American (March 1979): 94-110.

Lamb, Willis E. “Fine Structure of the Hydrogen Atom by a Microwave Method.” The Physical Review 72, no. 3 (1947): 241-243.

———. “Fine Structure of the Hydrogen Atom Part I.” The Physical Review 79, no. 4 (1950): 549-572.

———. “Fine Structure of the Hydrogen Atom Part II.” The Physical Review 81, no. 3 (1951): 222-232.

Hansch, Theodor W., et al. “Precision Measurement of the Rydberg Constant by Laser Saturation Spectroscopy of the Balmer Alpha Line in Hydrogen and Deuterium.” The Physical Review Letters 32, no. 24 (1974): 1336-1340.

Mohr, Peter J. “Lamb Shift in a Strong Coulomb Potential.” The Physical Review Letters 34, no. 16 (1975): 1050-1052.

Lee, S. A., R. Wallenstein, and T. W. Hansch. “Hydrogen 1S-2S Isotope Shift and 1S Lamb Shift Measured by Laser Spectroscopy.” The Physical Review Letters 24, no. 19 (1975): 1262-1266.

Selected Resources

HORIBA Scientific Tutorial on Optics and Spectroscopy

Hyperphysics Tutorial on Broadening of Spectral Lines

Course Info

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Fall 2016
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