Figure 8.

Picosecond resonance Raman spectra of ground-state rhodopsin, the excited-state transient (<700 fs), photorhodopsin (2 ps), and bathorhodopsin (10 ps). The excited-state spectrum is a Stokes Raman double difference spectrum in which ground-state photoproduct peaks present at 2 ps are removed from the 0 ps photoproduct spectrum, yielding positive peaks due to the transient 0 ps species along with small derivative features resulting from the anharmonically shifted ground-state peaks.