Laudatio 2005

Awarded Contribution:

Nuclear Magnetic Relaxation, by N. Bloembergen, E. M. Purcell, and R. V. Pound, Nature, 160, 475-476, (1947).

This paper contains all the essential ideas and results that were later described in greater detail in Bloembergen's PhD thesis (Leiden, 1948) and in the "BPP" paper, N. Bloembergen, E. M. Purcell, and R. V. Pound, Relaxation Effects in Nuclear Magnetic Resonance Absorption, Phys. Rev. 73, 679-712 (1948). A preliminary report was given by Bloembergen as a Contributed Paper at the APS meeting in New York in late January 1947 (N. Bloembergen, R. V. Pound, and E. M. Purcell, The Width of the Nuclear Magnetic Resonance Absorption in Gases, Liquids, and Solids, Phys. Rev. 71, 466 (1947) ).

The Prize Winner:
Bloembergen.jpg Nicolaas Bloembergen,

Professor of optical sciences,
University of Arizona,
Tucson, Arizona, USA,

Gerhard Gade University Professor Emeritus,
Division of Applied Science and Physics Department, Harvard University, Cambridge, Massachusetts USA.
The Technology:

The awarded paper proposed a semi-quantitative prediction for Bloch's relaxation times T1 and T2, based on an appropriate adaptation of transition probability theory (as originally presented by Weisskopf and Wigner) combined with the assumption that relaxation is dominated by the effects of molecular Brownian motion on a "fluctuating local field" acting on each spin. The paper introduced the notion of "motional narrowing" and established NMR as an essential tool for the experimental study of molecular motion, a situation that still persists today.