Sayyiduna Anas ibn Malik (radiyallahu ’anhu) reports that it was the noble practice of our beloved Rasulullah (sallallahu ‘alayhi wasallam) after every Fard Salah to place his right hand on his forehead (and in some narrations: on his head) and recite the following supplication: Bismillahillazhy la ilaha illa huwa-Rahmanu-Rahim. Allahumma Azh-hib ‘annil-hamma wal-huzn.(Translation:In the name of Allah, besides whom there is none worthy of worship, The most Gracious, The most Merciful.O Allah! Remove from me worry and depression)....... (Imams: Ibn-Sunni, pg.101 Hadith:112, Al-Tabarani, Al-Mu’jamul-Awsat Hadith: 2520 and Kitabu Du’a, pg.210 Hadith: 659; Bazzar; Kashful Astar vol. 4 pg. 22, Khatib Al-Baghdadi, Tarikh-Baghdad, vol.12 pg.480-481, Abu Nu’aym, Al-Hilyah, vol.2 pg.341-342 Hadith: 2493 and Ibn ‘Adiy, Al-Kamil, vol.7 pg.199. Also see Majma’uz-zawaid, vol.10, pg.110, Al-Adhkar of Imam Nawawi, Hadith: 191 and Malfuzat Faqihul Ummah, part.4 pg.14)