The widow of slain physician Michael Halberstam yesterdauy filed an $81, million lawsuit against Bernard C. Welch, the man convicted of Halberstam's murder, and asserted that the suit would serve as a warning to those who want to profit from her husband's death.

Elliot Jones, who called Welch "trash" after he was convicted by a D.C. Superior Court jury last week, called the lawsuit her revenge against Welch. Welch could be given 11 life sentences for his convictions of various charges, including first-degree murder, burglarly and larcency.

In another development, Welch's attorney, Sol. Z. Rosen, yesterday asked D.C. Superior Court Chief Judge H. Carl Moultrie I to grant Welch a new trial, based on what he called "prosecutorial misconduct." In court papers, Rosen told Moultrie that the U.S. Attorney's office failed to provide him certain information regarding the seizure of Welch's automobile by police until just before the trial. Rosen has challenged the validity of the seizure of evidence from the car.

Moultrie also ruled yesterday that Welch is elible for public funds for his legal fees. Moultrie's order said, however, that if funds ever become available, Welch must reimburse the government. Welch claimed indigency after the Internal Revenue Service filed $24 million in tax liens against him and his common-law wife, Linda Susan Hamilton.

Jones called her lawsuit, filed in U.S. District Court, "a warning to anybody -- authors, movie makers -- who think they are going to profit from Michael's murder. They just aren't going to get away with it." Jones cited published reports that book and magazine deals had been arranged for the convicted killer, and that a movie about Welch had been contemplated.

Jones acknowledged that it is unlikely that she would recover damaged from Welch until after the $24 million claim by the IRS against Welch and Hamilton is disposed of. An IRS spokesman confirmed that the government's claim will take precedence over Jones's.

Jones and others with claims against Welch could get some money if the IRS and Welch agreed to a lump-sum payment as settlement of the back taxes claim, according to IRS spokesman Robert J. Kobel, and some money remains. However, lump-sum settlements usually are made only after the government is convinced that it is impossible to recover larger due amounts.

Jones's lawsuit demands from Welch $77 million in punitive damages and $4 million in compensatory damages.

Welch was convicted last Friday of fatally shooting Halberstam as the noted cardiologist returned to his Northwest Washington residence on Dec. 5 and surprised a burglar. Welch will be sentenced by Moultrie May 22.