More than a hundred scientists gathered at Oxford University today to honor Dr. Veniamin G. Levich, but Levich himself will be here in his book-lined Moscow apartment, as he has for the past five years, virtually isolated from the scientific world to which he has made so many contributions.

Levich sorely wanted to attend the conference, arranged in his name to commemorate his 63th birthday and his work. At the three-day affair at one of the world's truly revered universities, scientists are to present dozens of papers in their specialties of physics and chemistry, and converse on the problems of atoms and of men.

Levich's hopes of attending, dim to begin with, will go unfulfilled, as will hopes of seeing his two sons and their families. For Levich, and many other Soviet citizens, are outcasts within their society. They are Jews who have been refused exit visas from the Soviet Union. 'Refused-niks' is how they sometimes refer to each other. They somprise a separate sub-group within this country of many nationalities and tongues.

Since 1970, about 130,000 of the Soviet Union's estimated 2.5 million Jews have emigrated and as many as 50,000 more have at least begun the process of seeking affidavits from relatives in Israel, th first serious official step toward seeking to emigrate. How many of these persons have been refused is unclear, but the signals can begin long before the actual request for an exit visa is actually denied. The shunning may start with expulsion from a job or an apartment and sometimes goes on for years.

This is the case with Levich, among the most prominent of Jewish scientists refused exit visas by the Soviet government on the stated ground that htework has put them in contact with state secrets. His story provides insight into the way life can be for some poeple here.

Five years ago, Veniamin Levich was near the pinnacle of a distinguished scientific career. He was a fprofessor at the prestigious Moscow State University and headed his own department of hydrodynamics, with more than 30 graduate degree candidates and a dozen academic instructors busying themselves at experiments and theories* theoritical work under his direction.

Levich's specialtyin the world of electrochemical kinetics, the study of how chemical and electrical properties of substances react under motion. His probes into his branch of physic and chemistry had opened new vistas for scientists and brought him an international reputation as a man making original and valuable contributions to science.

Then Levich committed what for the leadership of this society is a bitter affront - he applied to emigrate to Israel. News of his request fell "like a thunderbolt" among his fellow academicians, he recalled in a recent interview.

In short order, he was fired from his professorship and his positions as department head. His special chair at the university was eliminated. His name was removed from his published scientific papers and books and he was dismissed from various editorial board and advisory groups on which he had served.

He remains as a correspondent of the prestigious Academy of Scinens, but he is no longer able to participate in its activities. He had been shunned by friends, colleagues and students. His life of acceptance and recognition in the privileged world of Soviet science eneded as if it - and Levich himself - had never existed.

Over the years of his active career, however, he had built a strong reputation andand made friends elsewhere in the world. They mounted a massive letter-writing campaign on his behalf.

In 1973, one son, Yevgeny, a promising researcher but of frail health, was suddenly drafted and sent to a labor camp in Siberia. Intensive lobbying by Western scientists and dissident Nobel Laureate physicist Andrei Sakharov began. The son was returned to Moscow a year later.

In June 1974, just before the second visit here of President Nixon, Societ officials fearful of a protest or demonstration by refusedniks detained a number of them. Levich's treatment was a little different. Officials suddenly told him tah he and his wife, Tanya, and their two sons would be allowed to emigrate. Believing their assurances, Levich did nothing during the Nixon visit. The sons were allowed to leave in April 1975 but the parents were turned down.

Soviet officials told him his research work had given him contact with potential state secrets. He says he quit any defense-related work 28 years ago. He has been here evver since, waiting and sending letters, seeking help form outside. Behind his desk in a small room his high-ceilinged apartment in Lenisky Prospekt sit photographs of his two sons and their wives, grinning with their infants children for the camera.

"He lives in a spiritual ghetto, deprived of his family," said Tanya Levich. "it is an unequal contest, with a powerful and sophisticated machine on one hand and only individuals on the other."

"As a theoretician, I need only a pencil and formulae to work with," Levich said. "But the lab is essential to check the theories."