Measurement of the Balmer lines of atomic hydrogen and the fine structure of sodium lines; determination of the mass of the deuteron from the isotope shift. A high resolution monochromator with a wavelength range from 2500 to 15,000 angstroms in first and second order 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 quantum theory of the hydrogen spectrum, and a value of the Rydberg is derived. The transitions responsible for the sodium spectrum are identified, and the regularities in the fine structure and adherence to the selection rules are observed. A research grade monochromator is used to measure the isotope shift between the Balmer lines of hydrogen and deuterium, and the ratio of the deuteron mass to the proton mass is derived from the data.
Lab Guide (PDF)
A high resolution monochromator. (Image courtesy of Junior Lab staff.)
References
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.
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." Phys Rev 79, no. 4 (1950): 549-572.
———. "Fine Structure of the Hydrogen Atom Part II." Phys Rev 81, no. 3 (1951): 222-232.
———. "Fine Structure of the Hydrogen Atom." Nobel Prize Lecture. Stockholm, Sweden, 1955.
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.
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.
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.
Mohr, Peter J. "Lamb Shift in a Strong Coulomb Potential." The Physical Review Letters 34, no. 16 (1975): 1050-1052.
Arimondo, E., M. Inguscio, and P. Violino. "Experimental Determinations of the Hyperfine Structure in the Alkali Atoms." Review of Modern Physics 49, no. 1 (1977): 31-75.
Hansch, Theodor W., Arthur L. Schawlow, and George W. Series. "The Spectrum of Atomic Hydrogen." Scientific American (March 1979): 94-110.
Lee, S. A., R. Wallenstein, and T. W. Hansch. "Hydrogen 1S-2S Isotope Shift and 1S Lamb Shift Measured by Laser Spectroscopy." Physical Review Letters 24, no. 19 (1975): 1262-1266.
Selected Resources
Hyperphysics Tutorial on Broadening of Spectral Lines