The 26 suitcases, filled to bursting with letters, personal papers and more than 400 phonograph records collected over a lifetime that was brought to a standstill almost seven years ago by Soviet authorities, stood in neat piles in the dining room of the comfortable flat on Leninski Prospekt.

Only good enough for a one-way trip out," Tanya Levich said hopefully on Sunday. "Jewish suitcases."

The suitcases made it through Soviet customs inspection Tuesday, preceded earlier in November by 2 1/2 tons of books culled from a library built around careful inquiry into such things as the complexities of subatomic particles and Agatha Christie murders.

Today, Tanya Levich and her husband, Benjmain, the most prestigious Soviet scientist ever allowed to emigrate, bade their farewells at shabby Sheremetyevo Airport to relatives and friends they likely will never see again. And then they followed their belongings out of Russia to a place they have never seen, Israel, on the first leg of a journey that once seemed impossible.

"It is like going to another planet," Levich remarked amid the rueful smiles and tears at the airport. "It is a decision from which there is no turning back."

Later, after reaching Vienna, Levich said being allowed to emigrate was "kind of a miracle for me."

Levich, 61, made the decision to leave in January 1972, when his troubled conscience, sharpening by mounting anger over Soviet anti-Semitism following the 1967 Six Day War between the Israelis and Arabs, spurred him to apply with his family to go to Israel.

The Soviets, who had previously showered him with honor and privilege, quickly booted him out of the directorship of a physics institute he had founded and erased his name from dozens of scientific papers that had helped earn him a reputation as a brilliant physicist.

Levich kept his apartment, where he and his family had lived since 1963, and a stipend as corresponding member of the prestigious Academy of Sciences. But he lost his colleagues and his work.

Over the years of refusal, the Leviches were harassed and denounced and faced questioning by the KBG, the secret police. But they never faced the likelihood of jail or exile that has been brought down on others who, having been refused exit permission, become outspoken dissidents, such as Anatoly Scharansky. In part, this distinction reflected Levich's special status within the Soviet Union as a senior scientist.

He and his wife never became closely identified with the dissident movement that coalesced around the Helsinki monitoring group founded by Yuri Orlov, Alexander Ginzburg and Andrei Sakharov, the hydrogen bomb physicist turned human rights defender who was awarded the 1975 Nobel Peace Prize.

The Leviches' situation resembled that of many hundreds of other refused Jews not widely known in the West -- people who are not openly advocating reform of Soviet society, but who simply want to be let out.

Of the estimated 2.5 million Jews in the Soviet Union, as many as half a million may have begun the complicated steps necessary to obtain an exit visa, a privilege extended to only a handful of ethnic groups in this closed-border country. An informed Soviet source said recently that exit applications have risen "substantially" since the Camp David peace accords, which promise peace in the Middle East for the first time since the founding of Israel in 1948.

Longtime "refusedniks" at a press conference here last week suggested that other factors may be increased anti-Semitism in Soviet life and persistent rumors that authorities will refuse new exit applications in the new year.

The Soviets have raised emigration quotas this year from a January total of about 1,500 to about 4,000 in October, making 1978 the highest total since 1973, when more than 30,000 Jews were allowed to go. The total so far for 1978 is more than 20,000. The Soviets cut back the totals sharply in 1974 after the U.S. Congress tied trade to emigration.

The unexplained increase was evident at Sheremetyevo today, where the Levich departure was witnessed by dozens of nondescript Soviet travelers who had been waiting through the night to get their possessions through customs and whose only similarity to the Leviches turned out to be that they, too, were Jews.

The two Levich sons, Evgeny and Alexander, were allowed to leave in April 1975, but the parents were refused repeatedly on state security grounds. They drew support from prominent Western scientists and politicians, which angered and embarrassed the Soviets. When Sen. Edward M. Kennedy (D-Mass.) said he had raised the case and 17 others with Soviet leader Leonid Brezhnev during recent talks here, he was attacked in the Soviet press for intruding into internal Soviet affairs.