Intramolecular Photoassociation and Photoinduced Charge Transfer in Bridged Diaryl Compounds.7.A Semiempirical MO Study of Intramolecular Charge Transfer in the Excited Singlet States of Dinaphthylamines

1994 ◽  
Vol 98 (8) ◽  
pp. 2018-2023 ◽  
Author(s):  
Donghai Chen ◽  
Rovshan Sadygov ◽  
Edward C. Lim
Keyword(s):  
Charge Transfer ◽  
Intramolecular Charge Transfer ◽  
Excited Singlet ◽  
Photoinduced Charge Transfer ◽  
Singlet States ◽  
Excited Singlet States ◽  
Photoinduced Charge

An exciplex mechanism for the quenching of singlet excited states of aliphatic ketones by carbon tetrachloride

1976 ◽  
Vol 54 (5) ◽  
pp. 760-764 ◽  
Author(s):  
Rafik O. Loutfy ◽  
Allan C. Somersall
Keyword(s):  
Energy Transfer ◽  
Charge Transfer ◽  
Carbon Tetrachloride ◽  
Excited States ◽  
Excited Singlet ◽  
Decomposition Products ◽  
Classical Energy ◽  
Aliphatic Ketones ◽  
Singlet States ◽  
Excited Singlet States

Non-classical energy transfer from the excited singlet states of aliphatic ketones to carbon tetrachloride leads to sensitized decomposition products and fluorescence quenching. The correlation of the ionization potentials for a wide variety of such ketones with the corresponding quenching constants from fluorescence data has been rationalized by an exciplex mechanism. The correlation implies that charge transfer from the excited ketone to the carbon tetrachloride is a major contribution to the exciplex state for which two possible structures are tentatively proposed.

Dynamics of photoinduced charge-transfer in dimethylamino-substituted triphenylphosphines

1996 ◽  
Vol 93 ◽  
pp. 1697-1713 ◽  
Author(s):  
P Changenet ◽  
P Plaza ◽  
MM Martin ◽  
YH Meyer ◽  
W Rettig
Keyword(s):  
Charge Transfer ◽  
Photoinduced Charge Transfer ◽  
Photoinduced Charge

Photoinduced Charge Transfer Dynamics in Carotenoid-Porphyrin-C60 Triad via the Linearized Semiclassical Nonequilibrium Fermi's Golden Rule

2020 ◽  
Author(s):  
Zhengqing Tong ◽  
Margaret S. Cheung ◽  
Barry D. Dunietz ◽  
Eitan Geva ◽  
Xiang Sun
Keyword(s):  
Charge Transfer ◽  
Golden Rule ◽  
Time Dependent ◽  
Rate Coefficients ◽  
Initial State ◽  
Photoinduced Charge Transfer ◽  
Transfer Rates ◽  
Fermi's Golden Rule ◽  
Photoinduced Charge ◽  
Fermi’S Golden Rule

The nonequilibrium Fermi’s golden rule (NE-FGR) describes the time-dependent rate coefficient for electronic transitions, when the nuclear degrees of freedom start out in a <i>nonequilibrium</i> state. In this letter, the linearized semiclassical (LSC) approximation of the NE-FGR is used to calculate the photoinduced charge transfer rates in the carotenoid-porphyrin-C<sub>60</sub> molecular triad dissolved in explicit tetrahydrofuran. The initial nonequilibrium state corresponds to impulsive photoexcitation from the equilibrated ground-state to the ππ* state, and the porphyrin-to-C<sub>60</sub> and the carotenoid-to-C<sub>60</sub> charge transfer rates are calculated. Our results show that accounting for the nonequilibrium nature of the initial state significantly enhances the transition rate of the porphyrin-to-C<sub>60</sub> CT process. We also derive the instantaneous Marcus theory (IMT) from LSC NE-FGR, which casts the CT rate coefficients in terms of a Marcus-like expression, with explicitly time-dependent reorganization energy and reaction free energy. IMT is found to reproduce the CT rates in the system under consideration remarkably well.

scholarly journals Colloidal CdSe nanocrystals are inherently defective

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tamar Goldzak ◽  
Alexandra R. McIsaac ◽  
Troy Van Voorhis
Keyword(s):  
Charge Transfer ◽  
Energy Spectrum ◽  
Surface Structure ◽  
Short Range ◽  
Surface Defects ◽  
Low Energy ◽  
Lewis Base ◽  
Cdse Nanocrystals ◽  
Photoinduced Charge Transfer ◽  
Photoinduced Charge

AbstractColloidal CdSe nanocrystals (NCs) have shown promise in applications ranging from LED displays to medical imaging. Their unique photophysics depend sensitively on the presence or absence of surface defects. Using simulations, we show that CdSe NCs are inherently defective; even for stoichiometric NCs with perfect ligand passivation and no vacancies or defects, we still observe that the low energy spectrum is dominated by dark, surface-associated excitations, which are more numerous in larger NCs. Surface structure analysis shows that the majority of these states involve holes that are localized on two-coordinate Se atoms. As chalcogenide atoms are not passivated by any Lewis base ligand, varying the ligand should not dramatically change the number of dark states, which we confirm by simulating three passivation schemes. Our results have significant implications for understanding CdSe NC photophysics, and suggest that photochemistry and short-range photoinduced charge transfer should be much more facile than previously anticipated.

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