ATLANTA (AP) _ Federal prosecutors on Tuesday depicted a Florida millionaire accused of plotting the slaying of his socialite wife as a greedy man who hired an assassin to avoid large alimony payments.

The defense said the couple's divorce wasn't bitter enough to believe it was a motive for murder.

The conspiracy trial of James Vincent Sullivan, 51, of Palm Beach, Fla., got under way Tuesday with opening arguments in U.S. District Court.

Sullivan's wife, Lita, was shot at the door of her Atlanta home in January 1987 by a gunman who came to the door with a bouquet of roses.

She was killed just hours before a hearing in the couple's divorce in which she was seeking more than the $2,500-a-month alimony dictated by a pre-nuptial agreement. They had separated after 10 years of marriage.

''James Vincent Sullivan is a man who arranged to have other people commit the brutal execution of his wife,'' said Assistant U.S. Attorney Robert Schroeder. ''He is cheap and miserly. He didn't want to lose anything.''

Schroeder said he will use evidence of four phone calls made to or from Sullivan's Palm Beach, Fla., mansion to prove Sullivan arranged the murder.

Jurors will hear a phone call, tape-recorded by an acquaintance, in which Sullivan says the murder weapon was a 9mm gun with nine rounds, Schroeder said.

Sullivan pleaded innocent April 7 to five charges of using interstate commerce to arrange a murder for hire. If convicted, he faces a maximum of life in prison and a $1.25 million fine. He has been free on $2.8 million bail.

His attorney, Ed Garland, said prosecutors inflated the theory of a bitter divorce.

''This is a case about how an innocent man can be charged with a crime he didn't commit,'' Garland told jurors.

Garland said the divorce was no more bitter than most. Prosecutors contend Sullivan was desperate because his wife appeared to be in a good position to win a large share of his property, but Garland said Sullivan's divorce attorneys assured him he would win.

He noted that Sullivan gave his wife $300 a week in personal spending and household money, bought her a $440,000 Atlanta townhouse, furnished it lavishly and gave her a $75,000 ruby necklace.

''He had no motive to murder her, having spent lavishly on her,'' Garland said.

Sullivan made his millions from an inherited Macon liquor distributorship.

No state charges were filed. Federal charges resulted after FBI agents and state and local police found evidence of the alleged interstate conspiracy, Assistant U.S. Attorney William McKinnon has said.