Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
patter [ˈpætər] n (sound, of feet, rain) топота́ние; (of rain) стук; (sales talk etc) речитати́в
vi (footsteps) топота́ть*(impf) (rain) бараба́нить (impf)
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.