Spectral diffusion and [sup 14]N quadrupole splittings in absorption detected magnetic resonance hole burning spectra of photosynthetic reaction centers

Journal Article · Fri Apr 01 04:00:00 EST 1994 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.467242· OSTI ID:5212316

Greis, J W; Angerhofer, A ^[1]; Norris, J R ^[2]; Scheer, H; Struck, A ^[3]; von Schuetz, J U ^[1]

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1. 3 Physikalisches Institut, Universitaet Stuttgart, D 70550 Stuttgart (Germany)
2. Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
3. Botanisches Institut, Universitaet Muenchen, Menzinger Strasse 67, D 80638 Muenchen (Germany)

Zero field absorption detected magnetic resonance hole burning measurements were performed on photosynthetic reaction centers of the bacteria [ital Rhodobacter] [ital sphaeroides] R26 and [ital Rhodopseudomonas] [ital viridis]. Extrapolation to zero microwave power yielded pseudohomogeneous linewidths of 2.0 MHz for [ital Rhodopseudomonas] [ital viridis], 1.0 and 0.9 MHz for the protonated forms of [ital Rhodobacter] [ital sphaeroides] R26 with and without monomer bacteriochlorophyll exchanged, and 0.25 MHz as an upper limit for fully deuterated reaction centers of [ital Rhodobacter] [ital sphaeroides] R26. The measured linewidths were interpreted as being due to unresolved hyperfine interaction between the nuclear spins and the triplet electron spin, the line shape being determined by spectral diffusion among the nuclei. The difference in linewidths between [ital Rhodobacter] [ital sphaeroides] R26 and [ital Rhodopseudomonas] [ital viridis] is then explained by triplet delocalization on the special pair in the former, and localization on one dimer half on the latter. In the fully deuterated sample, four quadrupole satellites were observed in the hole spectra arising from the eight [sup 14]N nitrogens in the special pair. The quadrupole parameters seem to be very similar for all nitrogens and were determined to [kappa]=1.25[plus minus]0.1 MHz and [eta]=0.9[plus minus]0.1 MHz.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5212316
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 100:7; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

550200 -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
665100* -- Nuclear Techniques in Condensed Matter Physics -- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION SPECTRA
BACTERIA
CHEMICAL REACTIONS
DETECTION
DEUTERATION
EXTRAPOLATION
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MICROORGANISMS
NITROGEN 14
NITROGEN ISOTOPES
NUCLEI
NUMERICAL SOLUTION
ODD-ODD NUCLEI
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
RESONANCE
RHODOPSEUDOMONAS
SPECTRA
STABLE ISOTOPES
SYNTHESIS