2 y/o female chases older female

my moonlight is a very young looking, acting, healthy and agile 12 y/o burmese spay. she is delightful and sweet. spooky is a 2 y/o bombay spay (i got her from a breeder, she had one litter of kittens, now spayed) and i have had her for almost nine months. spooky is very smart, and sweet with people, but she has (in the last few months) started to dominate moonlight and chase her. i have tried talking very sternly to her and to catch her when she cases moonlight, and then separate them for about a half or or so. i also have to bring moonlight down from her third floor safety area often, so she will be around me and go through the house. she does often lay with me on my bed, until spooky jumps on the bed, then she will run away. moonlight will come down into the kitchen to eat, and spooky will even eat from the same plate as her most times.... but.... this chasing has changed moonight's personality. if moonlight is on one rung of the cat tree, spooky will climb up and bat at her. moonlight will bat back, but then runs away. i feel that spooky is trying to subordinate moonlight, and i feel so bad for my moonlight. they don't fight, nor hiss or anything, but it is not a good situation. spooky stares at moonlight and makes her very uncomfortable. anyone have any ideas as to what i could do? thank you.