Aleksei Abrikosov, leader of a theoretical physics group at Argonne National Laboratories, near Chicago, works in a quiet, dark office. He feels at home. He has no intention of changing jobs.

In 1989, Abrikosov was elected to lead the Institute of High Pressures at a prestigious scientific center outside Moscow, at Troitsk. But in 1991 he gave up all his academic privileges and settled permanently in the United States. He has not returned to his homeland since.Abrikosov states flatly that the entire elite sector of Russian theoretical physics has left for the West.

"I believe there are no really creative scientists left there," he says. "If I made a trip to Russia, I would not even have anyone to talk to. Sometimes when I am in an American or a German laboratory, I have a feeling that I have landed in some scientific council in one of Russia's institutes."

The brain drain from the former Soviet Union is one of the most widely discussed problems in science.

Since the 1980s, when the Soviet government began lifting controls on emigration, a large number of talented scientists have been heading for the West. Highest in demand are Russian mathematicians, physicists and biologists.

According to figures published this year by the Academy of Sciences, up to 80 percent of the country's world class mathematicians have left.

In the theoretical department of the Physics Institute, where Andrei Sakharov used to work, most of the 55 scientists work abroad at least part of the time, and more than half are away at any given moment.

Life in the West is not easy for the emigres. Under current Western economic conditions, even Western scientists have trouble finding steady employment.

Most Russians have to settle for temporary work. They become nomads, traveling from one laboratory to another - except those in Russia and other former Soviet republics.

A few organizations in Western Europe and the United States are trying to keep scientists in Russia by supporting them with stipends and research grants. A number of prominent American scientists are making great personal efforts to help their colleagues from the former Soviet Union.

But in Abrikosov's opinion, all these efforts combined will not stem the brain drain. The problem is not the number of people leaving so much as their quality, he says. Their departure is interfering with the process of regenerating scientific talent.

In time, he says, no one will be left in Russia to teach young scientists.

Still, Abrikosov believes this is no time for homesickness. He claims that emigre scientists understand perfectly well that nobody needs science in Russia right now.

Basic scientific research does not bring immediate profit. On the contrary, it requires financing, and the Russian coffers are empty.

A few years ago, Roald Sagdeev, now a physics professor at the University of Maryland and husband of the granddaughter of Dwight D. Eisenhower, was at the pinnacle of the Soviet scientific establishment.

He directed the best-endowed institute in the Academy, the Institute of Space Research. He had received all of the highest awards from the Soviet government.

He was even elected a deputy in the last Supreme Soviet of the Soviet Union.

Sagdeev came to a recent meeting in Washington by subway. Given his status, if he had used the subway in Moscow it would have been considered a public challenge - a sign of "political unreliability." But in Washington, Sagdeev does not find taking public transportation belittling.

Sagdeev is convinced that the majority of Russian scientists who have moved to the West maintain ties with the Russian science establishment.

He has received grants for programs involving Russian-U.S. cooperation, including research on potential uses of the Russian space reactor Topaz for the Strategic Defense Initiative and on the possibility of the cooperative orbital station called Freedom.

He thinks such joint projects offer the best hope of saving Russian science, citing as a successful example a NASA grant to a group in the Institute of Space Research, headed by Igor Mitrofanov, to study data received by the American orbiting laboratory.

But Abrikosov calls such proposals naive.

"I am convinced that it is useless to help science in Russia. You can raise the wages of scientists, but you cannot bring them instruments and equipment. Today there is only one way to maintain Russian science: To help all the talented scientists leave Russia and to ignore the rest."