ATLANTA — A chance encounter at a Georgia gas station left a 65-year-old woman dead and a 73-year-old man facing a murder charge after authorities say the woman’s car and his motorized wheelchair bumped, and he opened fire, police said Wednesday.

Linda Hunnicutt had just pulled into the gas station in Macon, shortly after 1 p.m. Tuesday and stepped out of her Buick Lucerne when the man pulled a gun and fatally shot her, city police spokeswoman Jami Gaudet said. ‘‘The whole encounter, I can tell you, was very brief,’’ Gaudet said.