Mario Savio, leader of the radical Free Speech Movement at Berkeley, Calif., in the 1960s, leaped to his feet and joined the chorus of Citizens' Party delegates chanting, "Move over . . . move over . . . move over . . ."

The infant party, comprised of first-generation liberal activists like Savio and their move youthful successors, had just nominated Barry Commoner, an environmental scientist at Washington University, as their presidential candidate at a convention here today.

Commoner said if big business and the political parties are unable to resolve the problems of energy, inflation and unemployment, "our answer is to them to move over, we'll do it."

"move over" immediately became the slogan for Commoner's campaign.

Savio and many of the 500 delegates and observers have known greater militancy than the party is offering and, indeed, many once found repugnant the very political system within which they are now working.

But the graying, balding Savio, now 37 and a math tutor in San Francisco, acknowledged he is "mellowing" and said, "i think we need to be moral but successful."

The convention was held in an aging hotel across the street from the Union Club, the seat of this city's corporate establishment. Several well-groomed executives watched with bewilderment as shabbily dressed delegates -- some barefoot, others in Indian garb, some carrying backpacks, children or bags of fast food -- emptied from rusting vans and marched into the hotel lobby.

Though claiming to be reform-minded, many of the delegates proved masters of old-style politics, displaying efective lobbying techniques on behalf of candidates and issues. The smoke-filled-room atmosphere was preserved as some of the same lobbyists even were able to beat down an antismoking resolution.

To the leadership of the new party, founded by Commoner and other activists last year, success is not winning the presidency but building an organization this year that could get 5 percent of the vote for the Commoner ticket in the November election.

This, party strategists say, would give the party a shade of credibility as an alternative to the Republicans and would add up to $7 million in retroactive federal election aid for future local and national political campaigns.

Commoner opposes nuclear power and says that corporations and their pawns in the established parties have ruined the nation.

He does not have the counterculture appearance, and wore a fashionable suit throughout the three-day convention that ended today.

He hopes to get on the ballot in at least 30 states where, he says, the 3,500 member party has organizations.

His running mate is LaDonna Harris, a Comanche Indian and the wife of Fred Harris, a former U.S. senator from Oklahoma. Their nominations are expected to be ratified in a Mailgram vote of members that begins this week.

Party strategist Jim McClellan, chairman of the campaign committee, believes the party has more to offer than the candidate most widely viewed as an alternative -- Rep. John B. Anderson.

The Citizens' Party, McClellan said, is better organized to wage a third-party campaign than Anderson and has a better chance to get on more ballots than the liberal Illinois Republican.

"anderson will run a personal campaign. We are building a party," said McClellan, who was chairman of Dr. Benjamin Spocks' 1972 presidential campaign. "once the election is past, the people who voted for Anderson will have nothing to show for it."

The party's credo is that corporate America, in search of maximizing profits, has often ignored the social concerns of the people, especially workers and minorities.

"the corporate big boys . . . are squeezing the American dream into this thimble," said author Studs Terkel in a keynote speech. "into this thimble you can put the difference between Jimmy Carter and Ronald Reagan and still have room for a shot and a beer."

Commoner cites this example of how politicians use public policy to protect corporate interests. In the mid-1950s, he says, oil companies abandoned domestic production of oil in favor of overseas production. Now that the supply of oil is threatened by Mideast political turmoil, both Carter and Reagan "are rattling their war swords" to protect corporate interests.

Commoner favors corporate accountability but does not specify how he would achieve this if elected. He ducked questions on the specifics of this plank in the party's platform, as well as a question on whether or not he favors, as the platform advocates, a U.S. admission of wrongdoing in Iran.

The party avoided a possibly divisive floor fight over the platform, opting to send it to the executive committee for further study.