On the Process of Space Quantization in Physical Review, Vol. 49, Second Series, January 1-June 15, 1936 pp. 324-328 [NUCLEAR MAGNETIC RESONANCE MOMENT, NMR]

Lancaster: American Institute of Physics, 1936. 1st Edition. FIRST EDITION OF RABI’S DESCRIPTION OF HIS THEORETICAL IDEA OF HOW TO MEASURE NUCLEAR SPIN, an idea that would lead to the determination of the signs of magnetic moments via his magnetic resonance method, the most significant improvement in molecular and atomic beam techniques to date” (Gonolis, Lindau Nobel Laureate Meetings). Rabi received the 1944 Nobel Prize “for his resonance method for recording the magnetic properties of atomic nuclei.”

The scientific community knew that “nuclei have intrinsic spins and magnetic moments. The magnetic moment has both a magnitude and a sign. [But] in 1935, the sign was missing. The sign of a magnetic moment can be either plus or minus: if the spin and the magnetic moment have the same space-quantized direction, the sign of the moment is plus; if these directions are opposed, the sign is minus… [But] as beamlets of a particular atom were refocused into the detector, the same pattern was observed regardless of whether the sign of the atom’s moment was plus or minus. The problem of determining the signs was something like trying to determine whether someone’s right hand or left hand is pushing the front-door buzzer” (Rigden, Rabi, 92).

Theoretical in nature, Rabi’s paper analyzes experiments carried out in Otto Stern’s Hamburg lab. As Stern had written: “The purpose of [the experiments] had been to answer a question that went back to the days of the old quantum theory, the days when the idea of space quantization strained credulity. The question was, Can an atom that is ‘clinging’ to a magnetic field with some particular space-quantized orientation be shaken loose? Can an atom be made to change its orientation” (ibid).

Of the idea for this paper, Rabi wrote:“One day I was walking up the hill on Claremont Avenue and I was thinking about it [the sign of the nuclear magnetic moment] kinesthetically with my body. Here’s the moment and its wobbling around in the direction of the field and [to find] the sign was to find out in which sense it was wobbling. To do this, I have to add another field which goes with it or against it.” “The whole resonance method goes back to this. His intuition was sound, and atoms did reorient in such a way that the signs of their magnetic moment could be determined” (Rigden, 93).

Rabi’s theory supposed that the effects of the spins of the nuclei, along with those of the electrons had to be considered in weak magnetic fields where the nuclear and electron angular momenta were significantly coupled together (Zeller). In his own words, Rabi believed it theoretically “possible to measure the sign of nuclear magnetic moment vector with respect to the spin vector” (Rabi, 324).

Rabi’s paper, this paper, "presented a theory that became the basis for the magnetic resonance method, determination of the signs of magnetic moments. [It] inaugurated a new era of precision: the experimental and theoretical difficulties that limited the precision of earlier results no longer existed” (Rigden, 94).

“After WW II, nuclear magnetic resonance (NMR) became a workhorse for physical and chemical analysis. Still later, Rabi’s discovery was extended to Magnetic Resonance Imaging (MRI), a powerful medical diagnostic tool, which is now used in medical centres the world over. In subsequent decades, the molecular beam method has been widely adopted by the physics and physical chemistry communities world wide, and about 20 Nobel Prizes were awarded for work based on the molecular beam method (Bonolis). Item #1658

CONDITION: 4to. Full volume. Bound in brown buckram. Ex-libris bearing bearing pictorial bookplate on paste down. Stamp on ffp, rffp & title page, the usual. Discreet gilt numbers at foot of spine. Tightly bound and clean. Very good.

Price: $225.00