scholarly journals XAO Analysis - AO's and Their Populations in Crystal Fields

10.5772/50517 ◽  
2012 ◽  
Author(s):  
Kiyoaki Tanaka ◽  
Yasuyuki Takenak
Keyword(s):  
Crystal Fields

200kv superconducting cryo electron microscope

1987 ◽  
Vol 45 ◽  
pp. 642-643
Author(s):  
M. Iwatsuki ◽  
Y. Kokubo ◽  
Y. Harada ◽  
J. Lehman
Keyword(s):  
Electron Microscope ◽  
Structure Analysis ◽  
Organic Materials ◽  
Strong Interactions ◽  
Specimen Preparation ◽  
Great Effort ◽  
Electron Microscopic ◽  
Crystal Fields ◽  
Special Skill ◽  
Long Time

In recent years, the electron microscope has been significantly improved in resolution and we can obtain routinely atomic-level high resolution images without any special skill. With this improvement, the structure analysis of organic materials has become one of the interesting targets in the biological and polymer crystal fields.Up to now, X-ray structure analysis has been mainly used for such materials. With this method, however, great effort and a long time are required for specimen preparation because of the need for larger crystals. This method can analyze average crystal structure but is insufficient for interpreting it on the atomic or molecular level. The electron microscopic method for organic materials has not only the advantage of specimen preparation but also the capability of providing various information from extremely small specimen regions, using strong interactions between electrons and the substance. On the other hand, however, this strong interaction has a big disadvantage in high radiation damage.

“Crystal fields” in metals and coefficients of fractional parentage

1982 ◽  
Vol 112 (1-2) ◽  
pp. 353-358
Author(s):  
J.M. Dixon ◽  
R. Chatterjee ◽  
R.S. Wardlaw
Keyword(s):  
Crystal Fields ◽  
Fractional Parentage

Electrochemical and spectroscopic characterization of a dicobalt macrocyclic Pacman complex in the catalysis of the oxygen reduction reaction in acid media

2013 ◽  
Vol 17 (04) ◽  
pp. 252-258 ◽  
Author(s):  
Qinggang He ◽  
Xiao Cheng ◽  
Ying Wang ◽  
Ruimin Qiao ◽  
Wanli Yang ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Reaction Pathway ◽  
Spectroscopic Characterization ◽  
Reduction Reaction ◽  
Acid Media ◽  
Crystal Fields ◽  
Mononuclear Cobalt ◽  
X Ray Absorption

The dicobalt complex [ Co2(L2) ] of a Schiff-base pyrrole macrocycle adopts a Pacman structure in solution and the solid state and shows much greater catalytic activity and selectivity for the four-electron oxygen reduction reaction (ORR) than the mononuclear cobalt phthalocyanine (CoPc) counterpart. Soft X-ray absorption spectroscopy (XAS) shows that the Co center in Co2(L2) is of the same valence as mononuclear CoPc . However, the former complex shows higher unoccupied Co 3d density which is believed to be beneficial for electron transfers. Furthermore, the XAS data suggests that the crystal fields for Co2(L2) and CoPc are different, and that an interaction remains between two Co atoms in Co2(L2) . DFT calculations imply that the sterically hindered, cofacial structure of the dicobalt complex is critical for the operation of the four-electron reaction pathway during the ORR.

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