Claudine Longet, pleading with a judge to have mercy on her as the mother of three children, was sentenced today to serve 30 days in jail "at a time of her own choosing" before Sept. 1 in the killing of her ski-champion lover.

Judge George Lohr expressed compassion for her and her family but said he felt releasing her with no jail time "might undermine respect for the law." He also put her on two years' probation. Maximum sentence for the misdemeanor is two years in prison and a $5,000 fine.

Charles V. Weedman, the entertainer's attorney, said he probably will ask next month for a new trial. He had said before sentencing he would appeal if his client received a jail term.

Lohr stayed the sentence until a motion for new trial is filed.

Longet's ex-husband and the father of her children, singer Andy Williams, wiped away tears as he sat through the half-hour hearing. He said afterwards, "I was hoping it wouldn't be" a jail sentence.

The 35-year-old former showgirl, convicted Jan. 14 of criminally negligent manslaughter in the shooting death March 21 of Vladimir (Spider) Sabich, told reporters she was not bitter.

"Because of the many cards and letters I've received, the prayers, I feel very good about everybody," she said.

Longet fought back tears as she stood before Lohr, pleading to save her children from the stigma of having their mother jailed.

"My children and I are very close," she said in a near whisper, adding that "they firmly believe in my innocence."

She said she believed the children - Noelle, 13, Christian, 11, and Robert, 7 - would become resentful "against a system that would sent to jail their mother they trust and believe in."

Sabich died of a single bullet wound in the stomach. Longet said the .22-cal. gun that killed him went off accidentally as he was teaching her how to use it.

The judge, noting he had received considerable mail from around the country about the case, indicated many Americans believe Longet guilty of murder.

He denounced what he said was the hostile attitude of Aspen residents against Longet. "The defendant will have to live with that for a long time," he said.