Excited complex: Its nature and applications (Conference Presentation)

2018 ◽  
Author(s):  
Jang-Joo Kim ◽  
Chang-Ki Moon ◽  
Hwang-Bum Kim
Keyword(s):  
Excited Complex

scholarly journals Halogen-Bond Assisted Photoinduced Electron Transfer

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4361
Author(s):  
Bogdan Dereka ◽  
Ina Fureraj ◽  
Arnulf Rosspeintner ◽  
Eric Vauthey
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Ground State ◽  
Halogen Bond ◽  
Quenching Rate ◽  
Excited Complex ◽  
Diffusion Controlled ◽  
Donor Acceptor ◽  
Quenching Rate Constant ◽  
Excited State Population

The formation of a halogen-bond (XB) complex in the excited state was recently reported with a quadrupolar acceptor–donor–acceptor dye in two iodine-based liquids (J. Phys. Chem. Lett. 2017, 8, 3927–3932). The ultrafast decay of this excited complex to the ground state was ascribed to an electron transfer quenching by the XB donors. We examined the mechanism of this process by investigating the quenching dynamics of the dye in the S1 state using the same two iodo-compounds diluted in inert solvents. The results were compared with those obtained with a non-halogenated electron acceptor, fumaronitrile. Whereas quenching by fumaronitrile was found to be diffusion controlled, that by the two XB compounds is slower, despite a larger driving force for electron transfer. A Smoluchowski–Collins–Kimball analysis of the excited-state population decays reveals that both the intrinsic quenching rate constant and the quenching radius are significantly smaller with the XB compounds. These results point to much stronger orientational constraint for quenching with the XB compounds, indicating that electron transfer occurs upon formation of the halogen bond.

Fluorescence of Excited Complex Molecules in Mercury Photosensitization

1966 ◽  
Vol 45 (6) ◽  
pp. 2322-2323 ◽  
Author(s):  
S. Penzes ◽  
O. P. Strausz ◽  
H. E. Gunning
Keyword(s):  
Complex Molecules ◽  
Excited Complex

scholarly journals Nonsequential double ionization of Mg from a doubly excited complex driven by circularly polarized laser field

2017 ◽  
Vol 25 (2) ◽  
pp. 1288 ◽  
Author(s):  
Shuai Ben ◽  
Pei-Ying Guo ◽  
Kai-Li Song ◽  
Tong-Tong Xu ◽  
Wei-Wei Yu ◽  
...  
Keyword(s):  
Laser Field ◽  
Double Ionization ◽  
Circularly Polarized ◽  
Excited Complex ◽  
Doubly Excited ◽  
Nonsequential Double Ionization

Unusually strong emission from an exciplex formed between benzenoid solvents and dibenzoylmethanatoboron difluoride. Formation of a triplex

1995 ◽  
Vol 73 (11) ◽  
pp. 1902-1913 ◽  
Author(s):  
Pierre Valat ◽  
Véronique Wintgens ◽  
Yuan L. Chow ◽  
Jean Kossanyi
Keyword(s):  
Quantum Yield ◽  
Rate Constant ◽  
Fluorescence Quantum Yield ◽  
Equilibrium Constants ◽  
Back Reaction ◽  
Benzene Derivative ◽  
Exciplex Formation ◽  
Excited Complex ◽  
Low Concentrations ◽  
Dibenzoylmethanatoboron Difluoride

Benzene derivatives give, in cyclohexane solution, a strongly emitting (Φf up to 0.8) excited complex with dibenzoylmethanatoboron difluoride (DBMBF2). The rate constant kex for the complex formation varies between 3.5 × 109 and 2.6 × 1010 M−1 s−1 depending on the benzene derivative, and the complex emission can already be detected at very low concentrations of the aromatics. This behaviour is different from that found in acetonitrile where the DBMBF2 emission disappeared completely before the new emission of the complex could be detected. The position of the complex emission and its lifetime depend upon the redox potential of the aromatics: the lower the latter, the longer the lifetime and the more the emission is red-shifted. The monotonous increase of the lifetime and of the fluorescence quantum yield of the emission with the concentration of the aromatics has been interpreted on the basis of an equilibrium between the exciplex and excited DBMBF2. The equilibrium constant varies with the electron-donating property of the aromatics, from 2.7 for benzene to 560 M−1 for isodurene. A decrease in the excited complex lifetime or in its fluorescence quantum yield is observed in some cases when the aromatics concentration is close to that of the pure solvent. Such behaviour is believed to arise from a new equilibrium resulting from the interaction of the exciplex with a second molecule of the aromatics to form triplex species. A detailed kinetic study has been undertaken in case of p-xylene, and the rate constants of all the processes involved in the double equilibrium have been determined. No basic difference is observed in the rate constant for exciplex formation when a single or double equilibrium is assumed; on the other hand, large discrepancies are found in the exciplex deactivation processes, specially for the back reaction from the exciplex to excited DBMBF2. The equilibrium constants between DBMBF2 and the exciplex, on one hand, and between the latter and the triplex are 56.6 and 0.68 M−1, respectively, when the concentration of p-xylene in cyclohexane is 3.3 M. Keywords: fluorescence, exciplex, triplex, dibenzoylmethanatoboron difluoride, kinetics.

SOME EFFECTS OF INTRAMOLECULAR VIBRATIONAL ENERGY TRANSFER IN COMPLEX FLUORESCENT MOLECULES

1958 ◽  
Vol 36 (1) ◽  
pp. 96-101 ◽  
Author(s):  
B. Stevens
Keyword(s):  
Energy Transfer ◽  
Energy Surface ◽  
Vibrational Energy ◽  
Complex Molecule ◽  
Three Dimensional ◽  
Fluorescence Emission ◽  
Vibrational Energy Transfer ◽  
Excited Complex ◽  
Continuous Absorption ◽  
Fluorescent Molecules

The effects of intramolecular redistribution of vibrational energy on both the fate of an excited complex molecule and the appearance of its electronic spectra are discussed in terms of a three-dimensional energy surface. It is suggested that continuous absorption be used as a criterion for the application of classical methods to intra- and inter-molecular vibrational energy transfer in those cases where fluorescence emission is observed.

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