Chemical Modeling of the Oxygen-Evolving Center in Plants. Synthesis, Structure, and Electronic and Redox Properties of a New Mixed Valence Mn−Oxo Cluster:  [Mn2III,IVO2(bisimMe2en)2]3+(bisimMe2en =N,N‘-Dimethyl-N,N‘-bis(imidazol-4-ylmethyl)ethane-1,2-diamine). EPR Detection of an Imidazole Radical Induced by UV Irradiation at Low Temperature

1996 ◽  
Vol 118 (11) ◽  
pp. 2669-2678 ◽  
Author(s):  
Yves-Michel Frapart ◽  
Alain Boussac ◽  
Rolf Albach ◽  
Elodie Anxolabéhère-Mallart ◽  
Michel Delroisse ◽  
...  
Keyword(s):  
Low Temperature ◽  
Uv Irradiation ◽  
Mixed Valence ◽  
Redox Properties ◽  
Chemical Modeling ◽  
Oxygen Evolving

scholarly journals Simulation of the isotropic EXAFS spectra for the S2 and S3 structures of the oxygen evolving complex in photosystem II

2015 ◽  
Vol 112 (13) ◽  
pp. 3979-3984 ◽  
Author(s):  
Xichen Li ◽  
Per E. M. Siegbahn ◽  
Ulf Ryde
Keyword(s):  
Photosystem Ii ◽  
Water Oxidation ◽  
Density Functional ◽  
Structural Changes ◽  
Complete Agreement ◽  
Oxygen Evolving Complex ◽  
Chemical Modeling ◽  
Oxygen Evolving ◽  
High Degree ◽  
Exafs Spectra

Most of the main features of water oxidation in photosystem II are now well understood, including the mechanism for O–O bond formation. For the intermediate S2 and S3 structures there is also nearly complete agreement between quantum chemical modeling and experiments. Given the present high degree of consensus for these structures, it is of high interest to go back to previous suggestions concerning what happens in the S2–S3 transition. Analyses of extended X-ray adsorption fine structure (EXAFS) experiments have indicated relatively large structural changes in this transition, with changes of distances sometimes larger than 0.3 Å and a change of topology. In contrast, our previous density functional theory (DFT)(B3LYP) calculations on a cluster model showed very small changes, less than 0.1 Å. It is here found that the DFT structures are also consistent with the EXAFS spectra for the S2 and S3 states within normal errors of DFT. The analysis suggests that there are severe problems in interpreting EXAFS spectra for these complicated systems.

Low-temperature modulation of the redox properties of the acceptor side of photosystem II: photoprotection through reaction centre quenching of excess energy

2003 ◽  
Vol 119 (3) ◽  
pp. 376-383 ◽  
Author(s):  
Alexander G. Ivanov ◽  
Prafullachandra Sane ◽  
Vaughan Hurry ◽  
Marianna Król ◽  
Dimitry Sveshnikov ◽  
...  
Keyword(s):  
Low Temperature ◽  
Photosystem Ii ◽  
Excess Energy ◽  
Redox Properties ◽  
Temperature Modulation ◽  
Reaction Centre ◽  
Acceptor Side

scholarly journals Effects of UV Irradiation on the Sensing Properties of In2O3 for CO Detection at Low Temperature

Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 338 ◽  
Author(s):  
Lucio Bonaccorsi ◽  
Angela Malara ◽  
Andrea Donato ◽  
Nicola Donato ◽  
Salvatore Gianluca Leonardi ◽  
...  
Keyword(s):  
Low Temperature ◽  
Indium Oxide ◽  
Uv Irradiation ◽  
Operating Mode ◽  
Semiconductor Layer ◽  
Experimental Conditions ◽  
Sensing Material ◽  
Resistive Sensor ◽  
Co Detection ◽  
P Type

In this study, UV irradiation was used to improve the response of indium oxide (In2O3) used as a CO sensing material for a resistive sensor operating in a low temperature range, from 25 °C to 150 °C. Different experimental conditions have been compared, varying UV irradiation mode and sensor operating temperature. Results demonstrated that operating the sensor under continuous UV radiation did not improve the response to target gas. The most advantageous condition was obtained when the UV LED irradiated the sensor in regeneration and was turned off during CO detection. In this operating mode, the semiconductor layer showed an apparent “p-type” behavior due to the UV irradiation. Overall, the effect was an improvement of the indium oxide response at 100 °C toward low CO concentrations (from 1 to 10 ppm) that showed higher results than in the dark, which is promising to extend the detection of CO with an In2O3-based sensor in the sub-ppm range.

Sign in / Sign up

Export Citation Format

Share Document