TY - JOUR T1 - Primary step in bacteriorhodopsin photosynthesis: Bond stretch rather than angle twist of its retinal excited-state structure JF - Journal of the American Chemical Society Y1 - 1998 A1 - Song, Li A1 - El-Sayed, Mostafa A VL - 120 SN - 0002-7863 N1 - Song, L El-Sayed, MA M3 - 10.1021/ja980390d ER -