Articles you may be interested inCross sections and photoelectron angular distributions in photodetachment from negative ions using equation-ofmotion coupled-cluster Dyson orbitals Threshold laws for the cross section for photodetachment of electrons from polyatomic negative ions are derived. The general form for the limiting behavior at threshold is derived using group theory and symmetry considerations. In addition, for energies within a few eV of threshold, a formulation using the Born approximation with partial orthogonalization is developed. The energy dependence of the photodetachment cross section for molecular negative ions is computed and shown to agree well with experimentally determined cross sections.

The kinetics of nickel electrode discharge are found to be controlled by solid‐state proton diffusion under normal high rate discharge conditions. As the nickel electrode is discharged, the conductivity of the active material decreases until eventually mixed kinetics are observed where the electrode impedance has significant contributions from both proton diffusion and charge transfer resistance. Further discharge results in the formation of a semiconductor layer at the metal‐active material interface that is depleted in charge carriers and has a relatively high electronic resistance. The depletion layer is responsible for the secondary discharge plateau of the nickel electrode at 0.0 to −0.5 V vs. normalHg/normalHgO . Changes in electrode capacitance during depletion layer formation appear to provide a sensitive measure of the uniformity of electrode discharge. The effects of cobalt additives on the kinetics have been experimentally measured, and while cobalt does not change the discharge mechanism, it does increase the ionic and electronic conductivity of the active material allowing a greater depth of discharge before depletion layer formation.

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Photodetachment cross sections are measured as a function of photon energy for enolate anions formed by proton abstraction in the gas phase, using an ion cyclotron resonance spectrometer to trap and detect the ions. Electron affinities are determined from the photodetachment thresholds for the enolate anions from acetaldehyde, propionaldehyde, butyraldehyde, 3-pentanone, pinacolone, methyl acetate, acetophenone, 4-heptanone, 1,1,1 -trifluoroacetone, diisopropyl ketone, phenylacetaldehyde, acetyl fluoride, acetone, 3,3-dimethylbutanal, and 2-butanone. The cross section shapes are analyzed in terms of a theoretical model for photodetachment, and we conclude that each cross section is composed of many vibronic transitions. We find evidence for electronic transitions in some of these anions in the blue and UV regions of the spectrum. Finally, substituent effects on anion stabilities are discussed and compared with the corresponding effects in solution.