Intense super radiation at 404.7 nm (73S1 ~ 63P0), 435.8 nm (73S1 ~ 63P1) and 546.1 nm (73S1~ 63P2)from atomic Hg produced by photodissociation of HgBr2 and HgI2 respectively with an ArF exoimer laser at 193nm and a KrCl excimer laser at 222nm has been observed. The mechanism of selected excitation of Hg(73S1) state is discussed.