Pump Probe Anisotropy Studies of the Photosynthetic Reaction Center

D C Arnett,P L Dutton,C C Moser,N F Scherer

doi:10.1155/1999/47101

Abstract

The photosynthetic reaction center of Rb. sphaeroides is investigated by unique pump-probe anisotropy methods using 13 fs optical pulses tunable throughout the near IR absorption band. The time and wavelength resolved pump probe anisotropy transients yield detailed experimental descriptions of the energy levels, Py+ and Py- of the excitonically coupled special pair (P), and dynamics prior to charge separation, particularly energy transfer from the accessory bacteriochlorophylla's (B) to the special pair (P).

Highlights

The photosynthetic reaction center of Rb. sphaeroides is investigated by unique pumpprobe anisotropy methods using 13 fs optical pulses tunable throughout the near IR absorption band
Much work has focused on the dynamics prior to and during charge separation in the photosynthetic reaction center [1], many issues remain unresolved, including the nature of the upper excitonic state of the electronically excited special pair (Py+, where P is the special pair ground state) and its influence on energy and electron transfer [2, 3]
The major Qy absorption bands are collectively excited using short (13-18fs) pulses with a broad spectral range, or individually excited with longer duration, spectrally narrowed pulses that overlap with the transition(s) of interest

Summary

Introduction

The photosynthetic reaction center of Rb. sphaeroides is investigated by unique pumpprobe anisotropy methods using 13 fs optical pulses tunable throughout the near IR absorption band. The time and wavelength resolved pump probe anisotropy transients yield detailed experimental descriptions of the energy levels, Py+ and Py- of the excitonically coupled special pair (P), and dynamics prior to charge separation, energy transfer from the accessory bacteriochlorophylla’s (B) to the special pair (P). Much work has focused on the dynamics prior to and during charge separation in the photosynthetic reaction center [1], many issues remain unresolved, including the nature of the upper excitonic state of the electronically excited special pair (Py+, where P is the special pair ground state) and its influence on energy and electron transfer [2, 3].

Results

Conclusion