scholarly journals Unlocking a Diazirine Long-Lived Nuclear Singlet State via Photochemistry: NMR Detection and Lifetime of an Unstabilized Diazo-Compound

2018 ◽  
Vol 140 (48) ◽  
pp. 16855-16864 ◽  
Author(s):  
Barbara Procacci ◽  
Soumya S. Roy ◽  
Philip Norcott ◽  
Norman Turner ◽  
Simon B. Duckett
Keyword(s):  
Singlet State ◽  
Diazo Compound

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.

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

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.

The Forbidden 11Bu– Excited Singlet State in Peridinin and Peridinin Analogues

2017 ◽  
Vol 122 (1) ◽  
pp. 130-139
Author(s):  
Jordan A. Greco ◽  
Nicole L. Wagner ◽  
Harry A. Frank ◽  
Robert R. Birge
Keyword(s):  
Singlet State ◽  
Excited Singlet State ◽  
Excited Singlet

ChemInform Abstract: Lowest Energy Excited Singlet State of Isolated cis-Hexatriene

ChemInform ◽  
2010 ◽  
Vol 22 (34) ◽  
pp. no-no
Author(s):  
W. J. BUMA ◽  
B. E. KOHLER ◽  
K. SONG
Keyword(s):  
Singlet State ◽  
Excited Singlet State ◽  
Excited Singlet
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