Dynamic electron transfer

From this equilibrium geometry, at t = 0, the nuclei move as follows. The interatomic distance of the upper pair of protons (D,) is decreased to the equilibrium distance for H2. The interatomic distance of the lower pair (Dj) is increased to the equilibrium distance for Hf. 

The original state at t = 0 is called the precursor state. The final state when the motion is completed with Dj = 0.7 A and D2 = 1.4 A is called the successor state. We integrate Equation 7.22 and read off the electronic density at the H, and H3 atoms (which is the same as the density at the H2and H4 atoms, respectively). 

At the successor state geometry, the lowest energy of the system is obviously when the upper system has two electrons and the lower system a single electron. 

FIGURE 7.5 Probability density at Hj as a function of D2 for different velocities v andR = 7B. 

The velocity is also important. The upper curve is obtained for a slow motion. The lower curve is obtained for a considerably faster motion. 

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Wang 0, Akhremitchev B and Walker G 0 1997 Femtosecond infrared and visible spectroscopy of photoinduced intermolecular electron transfer dynamics and solvent-solute reaction geometries Coumarin 337 in dimethylaniline J. Rhys. Chem. A 101 2735-8... 

Evans D G, Coalson R D, Kim H J and Dakhnovskii Y 1995 Inducing coherent oscillations in an electron transfer dynamics of a strongly dissipative system with pulsed monochromatic light Phys. Rev. Lett. 75 3649... 

These spectroscopic and theoretical developments have stimulated the recent advances on electron-transfer dynamics at ITIES. In addition to the correlation between structure and dynamics of charge transfer, fundamental problems in connection with the energetics of ET reactions remain to be fully addressed. We shall consider these problems primarily before discussing kinetic aspects in full detail. 

In bulk solution dynamics of fast chemical reactions, such as electron transfer, have been shown to depend on the dynamical properties of the solvent [2,3]. Specifically, the rate at which the solvent can relax is directly correlated with the fast electron transfer dynamics. As such, there has been considerable attention paid to the dynamics of polar solvation in a wide range of systems [2,4-6]. The focus of this chapter is the dynamics of polar solvation at liquid interfaces. 

Wang Q, Raytchev M, Fiebig T (2007) Ultrafast energy delocalization and electron transfer dynamics in 2-aminopurine-containing trinucleotides. Photochem Photobiol 83 637-641... 

Electron-Transfer Dynamics in Ti02/ Sensitizer Systems... 

In summary, electron transfer dynamics, mediated through saturated hydrocarbon bridges and proteins, displays a surprisingly weak distance dependence behaviour (/J = 0.8-12 A 1), compared to that predicted for a pure through-space mechanism (P 3.0 A1). 

Modulation of Electron Transfer Dynamics by Electric Fields... 

Electron spin resonance (esr), 22 132 for lignin characterization, 15 10 Electron-stimulated desorption-ion angular distribution (ESDIAD), 24 74 Electron transfer (ET), 9 376-381, 388 mechanisms of, 13 444 rate constant for, 13 447 Electron-transfer dynamics, in... 

When conformational change and electron transfer are concerted, the structural change may be treated as an internal reorganization factor in the electron transfer dynamics. This is the A, term of the Marcus-Hush model (Section 1.4.2 see also Section 1.4.4 for experimental examples). The model is applicable as long as the conformational changes are not so strong as to invalidate the harmonic approximation. 

Section 3, are commonly classified as inner-sphere (contact) ion pairs (Kochi, 1988). Accordingly, in organic and organometallic processes a strong distinction must be made in their behaviour from that of other less common outer-sphere ion pairs that are pertinent to the Marcus treatment of electron-transfer dynamics (Eberson, 1987 Lee et al., 1991). 

C. Period Orbit Analysis of Electron-Transfer Dynamics... 

The photoinduced electron-transfer dynamics has also been examined for a series of porphyrin-fullerene-linked molecules with the same spacer employed for Fc-ZnP-H2P-C6o ZnP-Ceo (edge-to-edge distance Ree = 11-9 A), Fc-ZnP-Ceo (Ree = 30.3 A) and ZnP-H2P-Ceo (Ree = 30.3 A), shown in Chart 1 [53]. The driving force dependence of the electron-transfer rate constants ( et) of these dyad, triads, and tetrad molecules is shown in Fig. 3, where log et is plotted against the driving force (-AGet) [47]. 

The synthesis of the triazolino[4, 5 l,2][60]fullerene 204, a novel donor-acceptor dyad exhibiting efficient electron-transfer dynamics, was reported by Guldi et al. (44) (Scheme 9.44). The azido tetrathiafulvalene 203, on heating with [60]fullerene in o-dichlorobenzene at 60 °C, gave the triazoline 204 in 24%... 

Murakoshi, K. Yanagida, S. Capel, M. Cashier, E. W., Jr. In Inteifacial Electron Transfer Dynamics of Photosensitized Zinc Oxide Nanoclusters, Moskovits, M. Ed. American Chemical Society Washington, DC, 1997, pp. 221-238. 

In Dr. M. Gratzel s plenary lecture at IPS-2000,103 he presented the following research topics to improve DSC. 1) Mastering the interfaces, electron transfer dynamics, control of dark current. 2) Charge transport in nanocrystalline films. 3) Panchromatic sensitizers, dye cocktail, quantum dot charge injection. 4) Light management, mixed metal oxide films, core-shell metal oxide films. 5) New... 

The heterogeneous electron transfer dynamics of a diverse range of organic and inorganic species and also the dynamics and energetics of ultrafast heterogeneous electron transfer dynamics of immobilized electroactive species on an electrode surface have been investigated with ultrafast voltammetry under a wide variety of experimental conditions of timescale, temperature, solvent, and electrolyte (see for example Fig. 5.16, obtained from [54]). 

A series of chlorophyll-like donor (a chlorin) linked having C60 (chlorin-C60) or porphyrin-C60 dyads with the same short spacer have been synthesized as shown in Schemes 13.1 and 13.2 [39, 40]. The photoinduced electron-transfer dynamics have been reported [39, 40]. A deoxygenated PhCN solution containing ZnCh-C60 gives rise upon a 388-nm laser pulse to a transient absorption maximum at 460 nm due to the singlet excited state of ZnCh [39]. The decay rate constant was determined as 1.0 X 10u s-1, which agrees with the value determined from fluorescence lifetime measurements [39]. This indicates that electron transfer from 1ZnCh to C60 occurs rapidly to form the CS state, ZnCh +-C60 . The CS state has absorption maxima at 790 and 1000 nm due ZnCh+ and C60, ... 

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