Jenny Rosenthal Bramley

MS 1927, PhD 1929, Advisor: Gregory Breit
H. Henry Stroke, 23, January 2002
These are some personal recollections of Jenny Rosenthal Bramley. For those of us, atomic physicist engaged in the study of hyperfine structure and isotope shifts, the name of Jenny Rosenthal is known from the very first. Hyperfine structure in the atomic spectrum displays the effect of magnetic and electric multipole interactions of the nucleus with the atomic electron. Isotope shifts come in a couple of varieties: mass-dependent effects with which we are familiar from elementary atomic physics, when we learn that hydrogen and deuterium have slightly displaced spectral lines caused by the differences in mass between the nuclei of 1H and 2H. What Jenny Rosenthal studied at the old University Heights campus in the Bronx was the effect of the spatial distribution of the nuclear charge on the electron-nuclear interaction. The work that she published with her advisor, Gregory Breit, The Isotope Shift in Hyperfine Structure, Phys. Rev. 41 459 (1932) accounted for both the overall shift in energy levels caused by the finite nuclear charge distribution and the isotopic differences caused by the changes in nuclear radius. This is known as the volume-dependent isotope shift: it served as one of the early ways to determine nuclear radii. She also calculated the effect of this distributed nuclear charge on the magnetic dipole hyperfine interaction and its isotopic effect. The latter has become known in the literature as the Breit-Rosenthal correction.
I met Jenny Rosenthal a half century after this work when she visited the Physics Department. She had left hyperfine structure and isotope shift after her thesis work, ending up working for the Army Ordnance. In talking with her I realized that she was completely unaware that her name was attached to an effect in physics and that the Breit-Rosenthal correction is used in the analysis of such experiments to this day. How many of us, working in physics, would be eager to have our name perpetuated in this way!
Jenny Rosenthal Bramley was a faithful alumna of New York University. She provided funds for an endowment to support spectroscopy in the Physics Department: the laboratory of Professor Tycho Sleator now carries the name "Jenny Rosenthal Bramley Laser Spectroscopy Laboratory".

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