Dynamic hole burning within special pair absorption band of Rhodobacter sphaeroides (R-26) reaction center at room temperature.

The absorbance spectrum of reaction centers of Rhodobacter sphaeroides at room temperature consists of relatively narrow spectral components which are moving in the femtosecond time scale and can be bleached by femtosecond laser pulses in the short wavelength region with a subsequent broadening and red shift of the bleaching (time constant approximately 250 fs). These data are discussed in terms of the population of the vibronic wave packets in the ground state by the interaction with phonons at 293K. The motion of these packets is probably responsible for the absorbance spectrum of the primary electron donor P at 293K with enhanced short wavelength components and with suppressed Stokes components.