Subpicosecond spectroscopy of bacteriorhodopsin.

Subpicosecond pulses have been used to study the ultrafast dynamics of the photochemistry of bacteriorhodopsin. An optically induced absorption that appears in about 1.0 picosecond at physiological temperatures has been resolved in time. The data can be interpreted in terms of the photochemical formation of bathobacteriorhodopsin and provide support for an excitation mechanisms involving molecular rearrangement in the protein induced by electron redistribution in the chromophore.