Glum Gorbachev’s Mood Brightens at Lunch With Celebrities : Reception: ‘We love you!’ crowd shouts as he hops from his limousine in the capital.

Beset by crises at home, Soviet President Mikhail S. Gorbachev displayed a serious and thoughtful mood for most--but hardly all--of his public appearances Thursday in a capital city of officials and experts anxious to gauge his demeanor.

In his most dramatic venture, in fact, Gorbachev, exhibiting his trademark unpredictability, hopped from his limousine a couple of blocks from the White House in the late afternoon for a little politicking and flesh-pressing.

As a handful of startled office workers and tourists looked on, Gorbachev stepped onto the sidewalk at the corner of Pennsylvania Avenue and 15th Street Northwest, across from the Treasury Building. The crowd soon swelled to about 100 people. As Gorbachev, followed closely by Secret Service and KGB agents, rushed into the crowd, many onlookers cried out: “We love you! We love you!”

Gorbachev began the day somewhat glumly but, as the good fellowship of the day progressed, his manner seemed to lighten. Both White House Press Secretary Marlin Fitzwater and Soviet presidential spokesman Arkady A. Maslennikov, in fact, insisted that Gorbachev, like Bush, was animated and in good spirits in their private meetings in the White House. But, for most of the day, the Soviet leader seemed troubled in public, though not depressed, sober though not somber.

Private Americans had their closest look at the Soviet President on two occasions--when he hosted a luncheon at the Soviet Embassy in honor of “American intellectuals” and later when he walked into the crowd near the White House.

The luncheon guest list included actress Jane Fonda; actors Gregory Peck, Douglas Fairbanks Jr., Burt Lancaster and Robert Redford; pianist Van Cliburn; trumpeter Dizzy Gillespie; playwright Arthur Miller; economist John Kenneth Galbraith; industrialist Armand Hammer; television mogul Ted Turner; television evangelist Robert Schuller; science fiction writers Ray Bradbury and Isaac Asimov; artists Andrew Wyeth and Robert Rauschenberg; black leader Jesse Jackson, former Sen. Eugene McCarthy and former Secretary of State Henry A. Kissinger.

Toasting his guests, Gorbachev made a plea for American understanding of his country’s plight as it tries to revolutionize its political and economic system.

“Like never before, we want to be understood right now,” he said.

Smiling slightly, he said that the Soviet people have to learn the market system from scratch; they have had no real experience with it. An American had told him, he recalled, that the Soviet Union must not hesitate about the market system--it must plunge in.

“ ‘You cannot be half-pregnant,’ ” he quoted the American as saying.

But, Gorbachev added, “It is also true that it takes nine months to produce a baby.” With a laugh, the Soviet president said that an aide had reminded him that a pregnancy sometimes ends one or two months earlier. In short, Gorbachev made it clear, the Soviet Union needs time, though it knows the time is limited.

Then Gorbachev, as if to show that he did not want to mask his seriousness in too much wit, turned abruptly from the laughter to re-emphasize his point.

“So we have to work on this,” he said. “Our people are not all prepared to accept this.”

Later, he astounded less prominent Americans by walking up to them near the White House. “When I saw him coming, I was just paralyzed. For the first time in my life, I was speechless,” said Helen Boussalis of Glendale, a professor of engineering at Cal State Los Angeles, who was in Washington for a convention of women engineers.

“I wanted to ask him a question about Germany, about the Russian economy, but I was so shocked I couldn’t speak. He looked so nice, so peaceful, just like a human being. He’s so different from on TV. He seems so cold and so serious.”

Another of the engineers, Charlena Grimes, an administrator at the engineering school at Washington State University, said that the only question she heard was a general query about whether the summit would lead to world peace.

“I couldn’t hear very well, but the translator said, ‘It’s not going to be easy, but we’re going to do it.’ The crowd then started shouting: “We love you! We love you.”

Added a stunned Grimes: “I can’t wait to get on the phone and start calling people, especially my 82-year-old father, and say: ‘Dad, there will be peace. There will.’ ”

Gorbachev began the day in an uncharacteristic way: standing silently, almost glumly, as President Bush read a speech of welcome on a platform set up on the South Lawn of the White House. Even when Bush thanked his visitor for bringing his wife, Raisa, back to Washington and thus bringing “joy to all our hearts,” Gorbachev made no gesture of acknowledgement.

As Bush escorted Gorbachev into the Oval Office in the White House, reporters started to pepper the Soviet leader with questions. But Gorbachev, who seemed to enjoy such banter at previous summits, warded them off.

“I’ve been told by the President that the current policy is there are no questions,” he said.

The luncheon at the Soviet Embassy filled most of Gorbachev’s time between his meetings at the White House. The American celebrities were obviously delighted with their celebrity host.

“What did he want with us?” said Asimov later. “Simply to make contact, to talk with the creative movers of the world . . . somebody other than politicians.”

The luncheon clearly put Gorbachev in a better mood. When he returned to the White House, he stopped to talk with American television reporters and did the same when he left the White House in late afternoon. He spoke glibly, so quickly that his interpreter had to interrupt from time to time to catch up in English. And then, as if to show that his mood had truly changed, at least for a while, he stopped his limousine and walked into the crowd.

Times staff writers John M. Broder and Shawn Pogatchnik contributed to this story.