Activation Free Energy of the Nonadiabatic Processes of Electron Transfer and the Reorganization Energy of the Inhomogeneous Nonlocal Medium

1996 ◽  
Vol 100 (14) ◽  
pp. 5721-5728 ◽  
Author(s):  
A. M. Kuznetsov ◽  
I. G. Medvedev
Keyword(s):  
Electron Transfer ◽  
Free Energy ◽  
Reorganization Energy ◽  
Activation Free Energy ◽  
Nonlocal Medium

scholarly journals The photo-physical study of the interaction of riboflavin with Nicotine in bicontinuous microemulsion

2017 ◽  
Vol 6 (6) ◽  
pp. 267-275
Author(s):  
Maurice Ohaekeleihem Iwunze
Keyword(s):  
Electron Transfer ◽  
Free Energy ◽  
Rate Constant ◽  
Reorganization Energy ◽  
Outer Sphere ◽  
Electron Transfer Reaction ◽  
Microemulsion System ◽  
Quenching Rate ◽  
Bicontinuous Microemulsion ◽  
Bimolecular Quenching

Steady-state fluorescence spectroscopy was used to study the interaction of riboflavin with nicotine in a bicontinuous microemulsion system made up of 42.11:13.70:21.34:22.85 % w/w of water: oil: surfactant: cosurfactant. The surfactant used is cetyltrimethylammonium bromide (CTAB), the oil is tetradecane and the cosurfactant is 1-pentanol. It is observed that the interaction of riboflavin and nicotine in the prepared microemulsion lead to the quenching of riboflavin fluorescence. The bimolecular quenching rate constant, kq, of riboflavin by nicotine was observed as 4.15 x 109 M-1 s -1 with an efficiency of 56 %. The mechanism of the reaction is proposed to be diffusion limited in an activated electron transfer reaction in a solvent separated (outer-sphere) scheme. The electron transfer rate constant, kET, was calculated as 5.89 x 109 s -1 with an activation rate constant, ka, of 9.52 x 109 s -1 . The calculated solvent reorganization energy, λs, of the reaction was 1.09 eV, the free energy of interaction, ΔGo , is -2.9 eV and the free energy of activation, ΔG*, was calculated as 0.75 eV.

scholarly journals Study of Electron Transfer between Amines and Biologically Active 4 - Aryloxymethylcoumarin

2016 ◽  
Vol 15 (1) ◽  
pp. 29-45
Author(s):  
U P Raghavendra
Keyword(s):  
Electron Transfer ◽  
Free Energy ◽  
Aromatic Amines ◽  
Reduction Potential ◽  
Standard Free Energy ◽  
Reorganization Energy ◽  
Biologically Active ◽  
Rate Parameter ◽  
Quenching Rate ◽  
Electron Transfer Theory

Electron transfer from aliphatic and aromatic amines to biologically    active    4-aryloxymethyl    coumarin1-(4- iodophenoxymethyl)-benzo[ f ]coumarin (1IPMBC)    has been investigated in acetonitrile solvent. The variation of quenching rate parameter with reduction potential of amines indicates the electron transfer from amines to investigated      coumarin molecule.Experimentally determined values of quenching rate parameter k q are well correlated with the standard free energy changes ( ∆G 0 ) within the framework of Marcus electron transfer theory. In the investigatedsystems,solvent reorganization energy appears to play a major role in governing electron transfer dynamics.

SOLVENT REORGANIZATION ENERGY WITH DIELECTRIC GREEN FUNCTIONAL AND ITS APPLICATION TO RETURN ELECTRON TRANSFER IN TETRACYANOETHYLENE-HEXAMETHYLBENZENE SYSTEM

2004 ◽  
Vol 03 (04) ◽  
pp. 609-627 ◽  
Author(s):  
QUAN ZHU ◽  
KE-XIANG FU ◽  
XIANG-YUAN LI ◽  
JI-FENG LIU
Keyword(s):  
Electron Transfer ◽  
Free Energy ◽  
Reorganization Energy ◽  
Energy Difference ◽  
Solute Molecule ◽  
Sphere Model ◽  
Free Energy Difference ◽  
Solvent Reorganization Energy ◽  
Electrostatic Free Energy ◽  
Non Equilibrium

Based on classical electrodynamics, the proper integral formula for general cases is adopted to estimate the electrostatic free energy difference between two given states, e.g. equilibrium and non-equilibrium states in the charging process of solute molecule in solution. With adequate consideration of the change of dielectric property in establishing the non-equilibrium state, the electrostatic free energy for this state can be obtained in a form differing from the traditional theories. The general formula of the solvent reorganization energy is derived according to the definition of the free energy difference between the non-equilibrium and equilibrium states due to the same electronic state of the solute molecule. Applying it to the two-sphere model and single-sphere model, we obtain the new expressions of the solvent reorganization energy, which are convenient to be used in practice. In the investigation of the return electron transfer of tetracyanoethylene-hexmethylbenzene system, good results can be obtained by using our expression when they are compared with those from the experiment.

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