Observation of a bacteriochlorophyll anion radical during the primary charge separation in a reaction center

Holzapfel, Wolfgang and Finkele, Ulrich and Kaiser, Wolfgang and Oesterhelt, Dieter and Scheer, Hugo and Stilz, Hans Ulrich and Zinth, Wolfgang (1989): Observation of a bacteriochlorophyll anion radical during the primary charge separation in a reaction center. In: Chemical Physics Letters, No. 160: pp. 1-7

Abstract

The primary light-induced charge separation in reaction centers of Rhodobacter sphaeroides was investigated with femtosecond time resolution. The absorption changes in the time range 100 fs to 1 ns observed after direct excitation of the primary donor P at 860 nm could only be explained by a kinetic model which uses three time constants. This finding supports the following reaction scheme: (i) the electronically excited primary donor P* decays with a time constant of 3.5 ps and populates a very short-lived intermediate involving a reduced accessory bacteriochlorophyll molecule; (ii) with a time constant of 0.9 ps the electron is transferred to the neighboring bacteriopheophytin molecule; and (iii) from there within 200 ps to the quinone.

• Item Type: Article
• Collections: Physics
• Subjects: 500 Science > 530 Physics