What is the expiation for rubbing against a girl during the daytime in Ramadan, fearing ejaculation, and is it permissible to give the expiation in money to charities?

Sincere repentance to Allah is obligatory for what was done during the daytime in Ramadan. If no semen was discharged, then the fast is valid and only repentance is required. However, if semen was discharged, then the fast is invalidated, and only a make-up day (qada') is required without expiation (kaffarah), according to the majority of scholars.