Martinus Veltman enjoys some champagne as he is congratulated by phone for receiving the 1999 Nobel Prize for Physics. (AFP)

By Curt Suplee
Washington Post Staff Writer
October 12, 1999

A method of taking unprecedented candid snapshots of chemical reactions with a shutter speed of a fraction of a trillionth of a second has won the Nobel Prize in Chemistry.

The physics prize, also announced in Stockholm today, goes to two Dutch-born theorists whose work in the 1970s helped make possible some of the most spectacular discoveries in modern physics, including the 1995 discovery of the elusive top quark.

The Royal Swedish Academy of Sciences awarded the $960,000 chemistry prize to Ahmed H. Zewail, 53, of California Institute of Technology in Pasadena, for devising a revolutionary laser technique that allows chemists to see, for the first time, how the atoms in molecules rearrange themselves step by step during even the most rapid chemical events.

The Egyptian-born Zewail's "femtosecond spectroscopy" involves two pulses of a high-speed laser. One excites the molecules that make up the ingredients of a reaction; a second, weaker, pulse then shows how the molecules have altered since the first pulse struck.

Gerardus 't Hooft, 53, and Martinus J.G. Veltman, 68, won the physics prize for tackling one of the most stubbornly baffling problems in modern physics: how to make sensible and mathematically accurate predictions from an insight that won a Nobel 20 years ago.

That prize was awarded for the discovery in the 1960s that two of the four fundamental forces of nature - namely, electromagnetism and the weak force that governs the nuclear decay of radioactive substances - were actually two aspects of the same thing. But the originators of that "electroweak" theory were unable to calculate the kinds of events and particles that might be found in experiments.

Veltman and 't Hooft found new mathematical techniques that predicted specific effects and values for electroweak interactions. Almost immediately, experiments began confirming the predictions, culminating in the 1995 discovery at Fermilab, outside Chicago, of a long-sought particle called the top quark that had almost exactly the characteristics predicted by the theorists. Quarks are the components of heavier particles such as protons and neutrons.

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