Parallel variation of mass transport and heterogeneous and homogeneous electron transfer rates in hybrid redox polyether molten salts

Metal complexes can be prepared as highly viscous (semisolid), room temperature molten salts by combining them with oligomeric polyether substituents. The fluidity and transport properties of these hybrid redox polyether melts can be systematically manipulated by changing the oligomeric chain lengths and by adding unattached oligomers as plasticizers. This paper describes the voltammetrically measured transport properties of several Co(II) polypyridine (2,2‘-bipyridine, phenanthroline) melts. The properties evaluated are the physical self-diffusion coefficient (DPHYS) of the cationic complex in its melt, the diffusivity of its counterion (DCION), the heterogeneous electron-transfer rate constant (kHET) of the Co(III/II) oxidation at the electrode surface, and the rate constant (kEX) for homogeneous electron self-exchange between Co(II) and Co(I) in the mixed valent layer next to the electrode. These dynamics parameters change in parallel manners, over a large (\u3e103) range of values, when the melt fluidity is changed by plasticizers or temperature. While kHET and kEX both change systematically with DPHYS, they change on a more nearly proportional basis with DCION. The latter relationship is interpreted as a kind of solvent dynamics control in which both the homogeneous Co(II/I) and heterogeneous Co(III/II) reaction rates are controlled by the ionic atmosphere relaxation time constant, namely, the time constant of redistribution of counterions following an electron-transfer step that has produced a nonequilibrium charge distribution. DCION provides a measure of the ion atmosphere relaxation rate

Implications of Bid Design and Willingness-To-Pay Distribution for Starting Point Bias in Double-Bounded Dichotomous Choice Contingent Valuation Surveys

ISSN:0924-6460ISSN:1573-150

Implications of Bid Design and Willingness-To-Pay Distribution for Starting Point Bias in Double-Bounded Contingent Valuation Surveys

We examine starting point bias in double-bounded dichotomous choice contingent valuation surveys. We investigate (1) the seriousness of the biases for the location and scale parameters of the willingness to pay (WTP) in the presence of starting point bias; (2) whether or not these biases depend on the distribution of WTP and on the bid design; and (3) how well a commonly used diagnostic for starting point bias\u2014a test of the null that bid set dummies entered in the right-hand side of the WTP model are jointly equal to zero\u2014performs under various circumstances. Monte Carlo simulations suggest that the effect of ignoring starting point bias depends on the bid design and on the true distribution of WTP. A well-balanced, symmetric bid design may result in very modest biases even when the anchoring mechanism is very strong. The power of bid set dummies in detecting starting point bias is low. They tend to account for misspecifications in the distribution assumed by the researcher for the latent WTP, rather than capturing the presence of starting point bias

The Subjective Well-being Construct: A Test of its Convergent, Discriminant, and Factorial Validity

construct validation, factor structure, subjective well-being,