The Sonoma County district attorney said no charges will be filed against the wife of Rockefeller heir Peter Prentice, who was shot to death in the bedroom of the couple's Santa Rosa home last month, because a 23-year-old daughter indicated the slaying was in self-defense. Dist. Atty. Gene Tunney said an attorney would not allow him to interview Andrea Prentice, but that the daughter, Alexendra Bens, claimed her father pointed a gun at both her and her mother. She heard the shot as she ran to telephone police, she said. Tunney said Prentice, a microbiologist and great grandson of oil tycoon John D. Rockefeller, had a high level of alcohol in his blood.