When senior Communist Party officials talk privately about President Carter these days there is a tone of keen disappointment, a feeling that a man whose promise some compared - perhaps naively - to John F. Kennedy has let them down and that chances for world peace are the poorer.

Whatever the outcome of Secretary of State Cyrus R. Vance's talks this week on strategic arms controls and other vital matters, the chagrin being expressed by leading Russians in conversations with Americans is likely to color relations between the two countries for some time.

Soviet indignation over what are considered here to be unnecessarily flamboyant displays of support for dissidents like the exile Vladimir Bukosvsky and physicist Andrei Sakharov has been loudly voiced by party leader Leonid Brezhnev, most recently in his initial meeting yesterday with Vance. Brezhnez said - and Soviet statements now constantly repeat - that "normal development" of ties with the United States is "impossible" unless such gestures are halted.

What that anger does not adequately convey, however, is the disillusionment official Russians profess.

At closed Communist Party meetings and similarly select Soviet gatherings that took place in the weeks before Carter's inaugural, "there was a sense that with this new President in the White House we could have a fresh start," one high-ranking Russian remarked. "There were parallels made to Kennedy, a belief that Carter was not the old-type American politician, that he would have an imaginative attitude.

"To my deep regret, I must say that opiniion has very quickly changed."

The turnaround came not merely because Carter issued declarations in support of human rights. "After all," one Soviet commented with a sly smile, "if all he did was speak generally about such rights, we could easily agree with him."

What rankled was that the President seemed so deliberately provocative, as though, in the words of another prominent Russian, "he had set himself a goal to spoil the atmosphere in the worst way he could."

The meeting on Feb. 28 with the 34-year-old Bukovsky was probably the most telling blow, the Russians say. Bukovsky had been imprisoned for anti-state activities.

"For the very great majority of our people," an official heatedly contended, "this man Bukovsky is a criminal, a traitor, scrum. Was it really necessary to see him even before Vance came here to establish high-level contacts."

Then there was the White House announcement last week on the day after Brezhnev's major speech denouncing U.S. support for dissidents as interference in Moscow's internal affairs that funds would be sought for 28 more transmitters to increase the range of Voice of America, Radio Free Europe and Radio Liberty. The Kremlin and its Communist allies still jam the latter two stations and charge that they "engage in subversive, anti-government, anti-Soviet, and anti-socialist propaganda," as one Russian commentator put it.

"I was astounded by this announcement," a generally cool-heated party functionary remarked. "It was really an awful thing to do on the eve of Vance's departure. It looked like the President wanted to make the situation even worse for his Secretary of State."

The Russians claim to be all the more puzzled because Carter had gone to some lengths before he took office to assure the Soviets that he wanted to see relations improved. Democratic Party elder statesman Averell Harriman spent three hours with Brezhnev last fall explaining the attitudes of then-candidate Carter and the Kremlin chief responded that, in effect, he would seek to prevent any confrontation from developing in the administration's early months.

"While there were different opinions about how relations might develop over the long term, everybody was sure that at least there would be a smooth beginning," a party official said. "I think there is a felling here that we were deceived by Carter."

Soviet sensitivities on the question of dissent are, of course, extremely acute and any forthright American pronouncements on the subject were bound to cause some displeasure. But highly sophisticated Soviet specialists in foreign affairs say it is the apparent precipitousness of Carter's actions that cause them as much or more concern than the actual crusade on behalf of human rights.

"Some people regard things like the meeting with Bukosvky or the increase in transmitters for Radio Liberty and Radio Fee Europe as a challenge," one such specialist explained, "an attempt to show that the United States will pursue positions that we consider typical of the Cold War."

"Or on the other hand," he said, "these are moves so incompetent, so unreliable, so badly thought through that we should be very worried about the future."

Yet for all the Russians stop well short of saying they cannot work productively with Carter. In every important speech, every major party pronouncement, the theme is the same. They say, "There is no alternative to detnte in a nuclear age."