Ultrafast pump-probe spectroscopy of two chemical systems: Photoactive yellow protein (PYP) and Prussian blue (PB)

Ultrafast pump-probe spectroscopy is presented for two chemical systems: photoactive yellow protein (PYP) and Prussian blue (PB). A novel, all-solid-state, acousto-optically Q-switched regenerative amplifier for femtosecond duration pulses is also presented. This amplifier is capable of amplification up to hundreds of microjoules in energy per pulse. Performance specifications of this amplifier are given.; Ultrafast pump-probe spectroscopy of PYP is presented with the pump at 400 nm and probe at 400 nm and 490 nm. An excited state absorption is seen for the first time at 400 nm. This excited state absorption decays biexponentially with time constants of τ = 760 fs and τ = 2.8 ps. A potential energy surface is proposed for PYP similar to one proposed for bacteriorhodopsin. A kinetic scheme is proposed that can explain all of the measurements taken. Anisotropy measurements reveal that there is little chromophore backbone bending within the time window of these measurements.; Ultrafast pump-probe spectroscopy of PB is presented with the pump at 800 nm and the probe at wavelengths from 690 nm to 840 nm. A 450 cm −1 mode associated with the MMCT is seen in the time-domain for the first time. The signals decay tri-exponentially in a wavelength-dependent fashion. Iron environment inhomogeneities are proposed as the source for the wavelength-dependent response.