Kinetics of the 580-nm ultrafast bacteriorhodopsin transient

We have observed, by low-temperature picosecond spectroscopy, a photo-induced transient at 580 nm in light-adapted bacteriorhodopsin. The transient was characterized by bleaching in the 550-585-nm regions within 6 ps and recovery in approximately 20 ps. The spectral intensity of the transient is found to be enhanced at lower temperatures, and the lifetime slightly elongated.