Nickel(II)-Methyl Complexes Adopting Idealized Seesaw Geometries

2019 ◽  
Author(s):  
Ethan A. Hill ◽  
Norman Zhao ◽  
Alexander S. Filatov ◽  
John Anderson
Keyword(s):  
Singlet State ◽  
Strong Field ◽  
Structural Distortion ◽  
Computational Results ◽  
Threefold Symmetry ◽  
Chelating Ligand ◽  
Electronic Stabilization

We report four-coordinate nickel(II)-methyl complexes of tris-carbene borate ligands which adopt rare seesaw geometries. Experimental and computational results suggest the structural distortion from threefold symmetry results from a combination of electronic stabilization of the singlet state, strong field donors, and constrained angles from the chelating ligand.

Nickel(II)-Methyl Complexes Adopting Idealized Seesaw Geometries

2019 ◽  
Author(s):  
Ethan A. Hill ◽  
Norman Zhao ◽  
Alexander S. Filatov ◽  
John Anderson
Keyword(s):  
Singlet State ◽  
Strong Field ◽  
Structural Distortion ◽  
Computational Results ◽  
Threefold Symmetry ◽  
Chelating Ligand ◽  
Electronic Stabilization

We report four-coordinate nickel(II)-methyl complexes of tris-carbene borate ligands which adopt rare seesaw geometries. Experimental and computational results suggest the structural distortion from threefold symmetry results from a combination of electronic stabilization of the singlet state, strong field donors, and constrained angles from the chelating ligand.

A Freeze-Etch Study of Acinetobacter SP. Grown on a Hydrocarbon Substrate

1974 ◽  
Vol 32 ◽  
pp. 174-175
Author(s):  
C. L. Scott ◽  
W. R. Finnerty
Keyword(s):  
Membrane System ◽  
Structural Distortion ◽  
Intracytoplasmic Membrane ◽  
Gram Negative ◽  
Sectioned Material ◽  
Acinetobacter Sp

Acinetobacter sp. HO-1-N, a gram-negative hydrocarbon oxidizing bacterium previously designated Micrococcus cerificans, has been shown to sequester the hydrocarbon into intracytoplasmic pools as a result of growth on this substrate. In hydrocarbon grown cells, an intracytoplasmic membrane system was also observed along with a doubling of cellular phospholipids (Z). However, using conventional dehydration and embedding procedures in preparing thin sectioned material, the hydrocarbon is extracted from the cells. This may lead to structural distortion, consequently, the freeze-etch technique was applied to preserve the integrity of the cell.

High resolution STEM imaging study on high Tc superconductor YBa2CuaO7-x

1988 ◽  
Vol 46 ◽  
pp. 882-883
Author(s):  
H.-J. Ou ◽  
J. M. Cowley
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Grain Boundary ◽  
Strong Field ◽  
Imaging Study ◽  
Structure Defects ◽  
High Tc ◽  
High Tc Superconductor ◽  
Diffraction Patterns ◽  
Lattice Planes

Using the dedicate VG-HB5 STEM microscope, the crystal structure of high Tc superconductor of YBa2Cu3O7-x has been studied via high resolution STEM (HRSTEM) imaging and nanobeam (∽3A) diffraction patterns. Figure 1(a) and 2(a) illustrate the HRSTEM image taken at 10' times magnification along [001] direction and [100] direction, respectively. In figure 1(a), a grain boundary with strong field contrast is seen between two crystal regions A and B. The grain boundary appears to be parallel to a (110) plane, although it is not possible to determine [100] and [001] axes as it is in other regions which contain twin planes [3]. Following the horizontal lattice lines, from left to right across the grain boundary, a lattice bending of ∽4° is noticed. Three extra lattice planes, indicated by arrows, were found to terminate at the grain boundary and form dislocations. It is believed that due to different chemical composition, such structure defects occur during crystal growth. No bending is observed along the vertical lattice lines.

Two-photon excitation fluorescence microscopy in living systems

1993 ◽  
Vol 51 ◽  
pp. 154-155 ◽  
Author(s):  
David W. Piston
Keyword(s):  
Confocal Microscopy ◽  
Fluorescence Microscopy ◽  
Singlet State ◽  
Excited Electronic State ◽  
Input Power ◽  
Two Photon ◽  
Simultaneous Absorption ◽  
Photon Excitation ◽  
Very High ◽  
Two Photon Excitation

Two-photon excitation fluorescence microscopy provides attractive advantages over confocal microscopy for three-dimensionally resolved fluorescence imaging. Two-photon excitation arises from the simultaneous absorption of two photons in a single quantitized event whose probability is proportional to the square of the instantaneous intensity. For example, two red photons can cause the transition to an excited electronic state normally reached by absorption in the ultraviolet. In our fluorescence experiments, the final excited state is the same singlet state that is populated during a conventional fluorescence experiment. Thus, the fluorophore exhibits the same emission properties (e.g. wavelength shifts, environmental sensitivity) used in typical biological microscopy studies. In practice, two-photon excitation is made possible by the very high local instantaneous intensity provided by a combination of diffraction-limited focusing of a single laser beam in the microscope and the temporal concentration of 100 femtosecond pulses generated by a mode-locked laser. Resultant peak excitation intensities are 106 times greater than the CW intensities used in confocal microscopy, but the pulse duty cycle of 10−5 maintains the average input power on the order of 10 mW, only slightly greater than the power normally used in confocal microscopy.

RADIATIVE COLLISIONS IN A STRONG FIELD REGIME

1985 ◽  
Vol 46 (C1) ◽  
pp. C1-85-C1-95
Author(s):  
P. Pillet ◽  
R. Kachru ◽  
N. H. Tran ◽  
W. W. Smith ◽  
T. F. Gallagher
Keyword(s):  
Strong Field

Eigenvalue Problem for the Second Order Differential Equation with Nonlocal

2006 ◽  
Vol 11 (1) ◽  
pp. 13-32 ◽  
Author(s):  
B. Bandyrskii ◽  
I. Lazurchak ◽  
V. Makarov ◽  
M. Sapagovas
Keyword(s):  
Differential Equation ◽  
Eigenvalue Problem ◽  
Variable Coefficient ◽  
Order Differential Equation ◽  
Integral Condition ◽  
Second Order ◽  
Computational Results ◽  
Discrete Method ◽  
Complex Eigenvalues ◽  
Nonlocal Integral Condition

The paper deals with numerical methods for eigenvalue problem for the second order ordinary differential operator with variable coefficient subject to nonlocal integral condition. FD-method (functional-discrete method) is derived and analyzed for calculating of eigenvalues, particulary complex eigenvalues. The convergence of FD-method is proved. Finally numerical procedures are suggested and computational results are schown.

The Gold Porphyrin First Excited Singlet State¶

2002 ◽  
Vol 76 (1) ◽  
pp. 47 ◽  
Author(s):  
Joakim Andréasson ◽  
Gerdenis Kodis ◽  
Su Lin ◽  
Ana L. Moore ◽  
Thomas A. Moore ◽  
...  
Keyword(s):  
Singlet State ◽  
Excited Singlet State ◽  
Excited Singlet
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