UCLA SCIENTIST AMONG SIX HONORED WITH NOBEL PRIZE.

Byline: William J. Broad The New York Times

The Nobel Prizes in physics and chemistry were awarded Wednesday to six scientists in the United States and Europe for advances in manipulating atoms and in understanding the basic chemistry of life.

Paul Boyer of the University of California, Los Angeles; John Walker of the Medical Research Council Laboratory of Molecular Biology in Cambridge, England; and Jens Skou of Aarhus University in Denmark shared the chemistry prize for their study of a tiny molecule that stores energy in all life on Earth.

Steven Chu of Stanford University, William Phillips of the National Institute of Standards and Technology, and Claude Cohen-Tannoudji of the College de France and Ecole Normale Superieure in France shared the physics prize for developing a way to trap atoms.

The method uses the concentrated light of lasers to cool gases to a temperature near absolute zero, which is -459.67 degrees Fahrenheit, and then keep the chilled atoms floating or captured, the blasts of laser light acting like a thick liquid to slow their movement. Individual atoms can then be studied in great detail.

The technique paved the way for the 1995 discovery of the Bose-Einstein condensate, a bizarre type of matter that had eluded experimenters ever since its existence was theorized by Albert Einstein more than 70 years ago. In this state, atoms can dramatically increase the area of space they occupy but still obey the rules of quantum mechanics, or the physics of the ultrasmall.

In its announcement, the Royal Swedish Academy of Sciences hailed the new techniques, which all derive from the basic discovery, as having ``contributed greatly to increasing our knowledge of the interplay between radiation and matter.''

Boyer and Walker won half of the chemistry prize for showing how all living things, from bacteria to humans, make adenosine triphosphate, or ATP, a tiny molecule that stores energy. The energy is tapped for such disparate tasks as building proteins, transmitting nerve impulses and contracting muscles.

In recent years, Boyer showed how an enzyme, ATP synthase, aids in the formation of ATP and Walker discovered the structure of the enzyme and verified the proposed mechanism. Enzymes are biological catalysts that promote thousands of chemical reactions within the cells of all living things, and the ATP enzyme is one of the most universal and important for life.

``ATP synthase has a mode of function that is unusual for enzymes,'' the Swedish Academy said in its announcement, ``and this required much time and extensive studies to establish.''

The other half of the chemistry prize was awarded to Skou, for discovering another enzyme involved in the chemistry of ATP.

This second enzyme, sodium-potassium stimulated adenosine triphosphatase, works like a pump to maintain the balance of sodium and potassium ions in living cells. Ions are atoms that have an electric charge and by nature are inclined to take part in reactions.

Inside cells, the concentration of sodium ions is usually lower and the concentration of potassium ions is higher than outside cells. The enzyme discovered by Skou maintains this chemical balance, which is critical for many life functions.

For instance, the disparity is necessary if a signal is to travel along a nerve fiber. Conversely, a shortage of nourishment or oxygen in the brain causes ATP formation to cease and the ion pump to close down, ending all nerve impulses and rapidly resulting in unconsciousness.

Skou ``was the first to describe an enzyme that can promote directed transport of substances through a cell membrane, a fundamental property of all living cells,'' the Swedish Academy said.

The Nobel Prizes in physics and chemistry are each worth $1 million and are widely considered a pinnacle from which scientists win the approbation of peers and public alike.

The slowing of atoms, for which the physics prize was given, removed a barrier to the study of these basic components of matter.

At room temperature, the atoms and molecules that comprise the air move over exceedingly short distances at speeds of up to 2,500 miles per hour, making them extremely hard to study. Lowering the temperature can slow them. As gases cool, they normally condense into liquids and then freeze into solids - states that pack constituent parts close together and impede study.

But in a vacuum - if densities are low enough to avoid condensation and if temperatures can be lowered to near absolute zero - free atoms can be slowed down to speeds of less than one mile per hour, allowing a close examination of their nature and properties.

Chu, working with colleagues at Bell Laboratories in Holmdel, N.J., focused a battery of very bright laser beams to achieve such cooling and slowing of atoms in 1985. After that, magnetic traps were added to give the atoms even more stability.

``I'm still the same person I was yesterday,'' Chu told reporters at Stanford on Wednesday. ``The moral is that you really shouldn't take these things that seriously.'' After a pause he added, ``I'm thrilled.''

CAPTION(S):

6 Photos

PHOTO (1) CHU

(2) PHILLIPS

(3) COHEN-TANNOUDJI

(4) BOYER

(5) WALKER

(6) SKOU