Electron solvents

In alicyclic hydrocarbon solvents with aromatic solutes, energy transfer (vide infra) is unimportant and probably all excited solute states are formed on neutralization of solute cations with solute anions, which are formed in the first place by charge migration and scavenging in competition with electron solvent-cation recombination. The yields of naphthalene singlet and triplet excited states at 10 mM concentration solution are comparable and increase in the order cyclopentane, cyclohexane, cyclooctane, and decalin as solvents. Further, the yields of these... 

Kevan (1974) and Tachiya (1972) point out that CKJ use an SCF approximation to calculate the medium polarization energy, but in everything else they use the adiabatic approximation. This somewhat inconsistent procedure, which may be called the modified adiabatic approximation, gives results similar to those obtained by FFK. Varying the dipole moment and the polarizability in the semicontinuum models varies the result qualitatively in the same direction. It increases the electron-solvent attraction in the first shell and also increases the dipole-dipole repulsion. Both hv and I increase with the dipole moment, but not proportionately. 

Catterall, R. (1976), in Electron-Solvent and Anion-Solvent Interactions (Kevan, L., and Webster, B., eds.), p. 45, Elseiver, Amsterdam. 

We have given some highlights of a theory which combines the familiar multistate VB picture of a molecular system with a dielectric continuum model for the solvent which accounts for the solute s boundary effects — due to the presence of a van der Waals cavity which displays the solute s shape — and includes a quantum model for the electronic solvent polarization. 

Figure 3.29. Cyclovoltammogram for the electron transporting material Spiro-PBD (40). The first reduction is a merged wave with an overall transfer of two electrons. Solvent THF/TBAHFP 0.1 M, Scan rate lOOmV/s.

The fewer factors that lower ion-radical stability, the more easily ion-radical organic reactions proceed. Because ion-radicals are charged species with unpaired electrons, solvents for the ion-radical reactions have to be polar too, incapable of expelling cationic or anionic groups that the ion-radical bears as well as chipping off radicals from it (especially to abstract the hydrogen atom). Static solvent effects can be subdivided on general and specific ones. 

The study of electron-solvent interactions in nonpolar monoatomic liquids (e.g., liquid rare gases) provides valuable information concerning the short range interactions between an excess electron and the solvent molecules. These studies provide an interesting model for electron localization arising from short range repulsions, as for liquid helium, and lead to a deeper understanding of the transition between the localized and delocalized states of an excess electron in simple fluids. 

It should be noted that, as in the previous analysis of the Schrodinger Equation (1.104), in the Fock matrix expression (1.108) we have used a single term to describe the one-electron solvent term. We remark, however, that in the original formulation two matrices, jR and yR, were used, namely ... 

If the electron solvent polarization is neglected, the study of electron transitions and the determination of the solvent shift do not require appreciable modifications in the basic scheme of ASEP/MD. During a Franck-Condon transition the solute and solvent nuclei remain fixed and hence the ASEP obtained for the initial state can be used for the rest of the states of interest. However, it is known that the electron degrees of freedom of the solvent can respond to the sudden change of the solute electron charge distribution. In fact, the polarization component can contribute appreciably to the final value of the solvent shift. The determination of this component requires additional calculations where the solute and solvent charge distributions are equilibrated. Each electronic state requires a separate calculation of the solvent polarization component. It is hence necessary to perform as many polarization calculations as electronic states being considered. 

BeUoni J, Marignier J-L. (1989) Electron-solvent interaction Attachment solvation competition. Radiat Phys Chem 34 157-171. 

To conclude this review, despite rapid progress, many outstanding questions about the solvated electron remain unanswered. The structure and the behavior of these unusual species turned out to be much more complex than originally believed. Further advances will require greater focus on the quantum-chemical character of the solvated electron explicitly treating the valence electrons in the solvent, and more realistic dynamic models of the solvent degrees of freedom and electron-solvent interactions. Developing a many-electron, dynamic... 

In nondonor solvents such as hexane, the iodine color remains essentially the same violet, but in benzene and other rr-electron solvents it becomes more red-violet, and in good donors such as ethers, alcohols, and amines the color becomes distinctly brown. The solubility of I2 also increases with increasing donor character of the solvent. Interaction of the donor orbital of the solvent with the 9a orbital results in a lower occupied bonding orbital and a higher unoccupied antibonding orbital. As a result, the TTg ---- CT transition for I2 + donor (Lewis base) has a higher energy and an ab-... 

The Physical Origin of Electronic Solvent Shifts. The motion of electrons in the solute sets up oscillatory fields in the solvent. The solvent thereby becomes... 

The addition (already about 15%) of a small amount of rr-electron solvents such as benzene improves the separation of the band of less polar taxoids (paclitaxel, cephalomannine) and closely eluted chlorophylls. 

In this simplified expression the electronic solvent molecule polarization is given in terms of the induced dipoles fimd, which may be calculated by... 

Our discussion follows A. Mozumder in Electron-solvent and anion-solvent interactions. L. Kevan and B. Webster, Editors (Elsevier, Amsterdam, 1976). 

Optimization of transport processes in porous electrode systems (gases, ions, electrons, solvents)... 

---