The mood of the crowds in Tehran, once they exulted over the return from exile of Ayatollah Ruhollah Khomeini, was almost subdued -- in contrast with the sustained jubilation that followed the departure two weeks ago of Shah Mohammad Reza Pahlavi.

Cheers and chants of the throungs, estimated at 2 million in all, reached a deafening crescendo as the 78-year-old Moslem leader went past. But after-ward, the quiet came quickly.

It was as if the people were caught up in wondering about what would happen next, and hope that the ayatollah's return after 14 years would solve Iran's deep economic and political problems.

The much heralded arrival, twice postponed last week becase the government closed the country's airports, got off to a chaotic start when news photographers and some of the ayatollahhs own supporters in the airport terminal building pressed toward him, causing a din of angry shouting and some scuffles with the millahs and "Islamic guards" assigned to shield him.

The score of uniformed police on hand at the terminal stayed well out of the way, as did the army, which for the previous two days had sealed off the area with troops and tanks. About 30 air force noncommissioned officers posted on the tarmac, some armed with submachine guns, were the only military presence at the ceremony, which was organized by the ayatollah's supporters.

After a sppech, Khomeini's motorcade headed into the city.But before it reached the nearby Shahyad monument -- erected by the shah to glorify the Persian monarchy -- the crowd swarmed in behind Khomeini's car, stranding buses of journalists who were supposed to follow him to the cemetery.

A half dozen gray-suited "Islamic guards" riding atop the ayatollahhs car kicked supporters away to prevent them from stopping the motorcade. Although guards discouraged them, a number of people shouted anti-American slogans at the stranded press buses.

People jammed every conceivable vantage point to catch a glimpse of the enigmatic ayatollah, atlhough in the end relatively few of them did. Youths climbed trees or sat on the top of bus shelters, telephone booths, railings, garden walls and parked vehicles. People lined rooftops and balconies and leaned out of windows.

Troops and policemen were nowhere to be seen. Order was kept by about 50,000 volunteer "Islamic police" recruited en masse before the ayatollah's arrival.

Khomeini's gaunt, white-bearded face with dark, deepset eyes, looked dwn from posters plastered on almost every wall and portraits and banners carried by the crowd.

At the Tehran tehnical university, dozens of posters portrayed the ayatollah's stern face side by side with the emblem of the Mujaheddin-e-Khalu, an Islamic guerrilla group. Another poster was of the shah. Its caption read: "Wanted dead or alive."

"We are very happy about his arrival and we hope that [Prime Minister Shahpour] Bakhtiar's government will fall soon," said a 55-year-old government worker named Mohammed. "And Islamic national republic is going to replace this treacherous, fascist regime."

Numberous other onlookers expressed similar opinions, often with a note of worry.

Mechanical engineer Majid Hashemi, 30, said, "The coming of Mr. Khomeini was necessary. But from now on his method of presenting himself to the people must be carefully thought out. He must separate religion from politics. His frame of references don't work in today's international system.But he shoul have a say in what politicians decide."

A 40-year-old bookseller named Jalal said, "In terms of political significance, things are just starting." He said he would prefer to see "a 100 percent democratic government come to power." Unless there could be a free exchange of ideas, "it won't be any different from previous regimes," he said, adding, "We are terribly afraid."

After the ayatollah addressed a huge crowd at Tehran's main cemetery, several thousand people gathered in a popular quarter of downtown Tehran near a rundown school where Khomeini reportedly intends to stay until he journeys to the holy city of Qom, south of the capital, to join other ayatollahs.

Formerly a girl's high school, the place was shut by the government four years ago because of "revolutionary" activities, according to one of the Islamic guards posted there.

The two-story brick school, the facade never completed, was decorated with huge posters of Khomeini and banners of welcome. One said: "You have returned to Iran healthy and victorious loke the prophet Mohammed to Mecca."

Located near Iran's lower house of parliament and the notorious Jaleh Square, the scene of all the shooting when martial law was declared last September, the school affords a rather dismal view of the capital. The building faces an abandoned construction site surrounded by a metal fence topped with barbed wire.