Electron spin echo detection of quantum beats and double-quantum coherence in spin-correlated radical pairs of protonated photosynthetic reaction centers

✍ Scribed by Sergei A. Dzuba; Martin K. Bosch; Arnold J. Hoff

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 454 KB
• Volume: 248
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(96)87702-5

✦ Synopsis

The spin-correlated radical pair [P+'Q~'] in protonated zinc replaced reaction centers of Rb. sphaeroides R26 is studied using electron spin echo spectroscopy. Applying a (flash-t-pulse 1-T-pulse 2-T) pulse sequence, it was found that the shape of the echo at T = ~-is influenced markedly by the delay t, for 0 < t < 40 ns. In addition a second echo signal was found at T = 27-for t = ~-. Both phenomena can be simulated well using the approach of Tang and Norris [Chem. Phys. Letters 233 (1995) 192]. The change in shape of the first echo (T = r) is ascribed to quantum beats; the second echo (T = 2T) is due to double-quantum coherence.