Sunday Night Havdalah

 https://ohr.edu/this_week/insights_into_halacha/9993

In Maariv on Motza’ei Shabbos-Tisha B’Av, we recite “Attah Chonantanu” to allow the performing of melachah (or by simply saying “Hamavdil Bein Kodesh L’Chol” once it is Tzeis Hakochavim at the conclusion of Shabbos). There is no bracha of Besamim at all - as that is considered hana’ah (benefit or pleasure), which we minimize on Tisha B’Av. It is also not recited on Motza’ei Tzom, when the fast ends on Sunday night, as at that point it is no longer directly after Shabbos.