Electron affinities determination

Electron affinity, determination, lattice energies and, 203-204 Electron transfer, correlated pairs,... 

Lattice energies, alkali metal salt values, amides and, 196 azides and, 198-199 bifluorides and, 199 borofluorides and, 203 borohydrides and, 197 chalcogenides and, 192,193 cyanates and, 199-200 cyanides and, 196-197 halides and, 189, 190 hydrides and, 189, 191, 192 hydrosulfides and, 195-196 hydroxides and, 192,194, 195 nitrates and, 201 superoxides and, 197-198 thiocyanates and, 200 alkaline earth salt values, acetylides and, 198 carbonates and, 202-203 chalcogenides and, 192, 193 imides and, 196 peroxides and, 198 calculation uses, absolute enthalpies and, 206 electron affinity determination and, 203-204... 

Figure 4.11 Morse potential energy curves for chloronaphthalene and its ions. The curves are calculated using the activation energy and electron affinity determined from the data in Figure 4.10. The high-temperature data are for sequential dissociation. For the two lowest curves the VEa and EDEA are negative, but molecular ion formation precedes dissociation in the Franck Condon transition.

Figure 5.13 A precision and accuracy plot of the atomic electron affinities determined before 1967 versus the current best values. The deviations from the unit slope and zero intercept line result from random and systematic errors.

The values of the atomic electron affinities determined before 1967 are plotted against the current EvV in Figure 5.13. This is a precision and accuracy (or P and A) plot. The plot of the electron affinities of the charge transfer acceptors (Figure 4.15) was also a P and A plot. It is used to concisely illustrate the quality of the experimental data. By comparing the data to a line with unit slope and zero intercept, an immediate picture of the precision (random) errors and accuracy (bias) errors can be visualized and outliers identified. By inspection the electron affinities of O (2 eV), Cl (4 eV), and F (4 eV) are suspected outliers. The higher values deviate... 

The TCT method of obtaining relative molecular electron affinities and gas phase acidities has a demonstrated precision of 0.05 to 0.10 eV in the midrange of values from 0.5 eV to 3.0 eV. At the extremes the precision is less, 0.2 eV. Most of the TCT Ea are ground-state electron affinities. The exceptions are the HPMS electron affinities determined for azulene, anthracene, QJv, and CS2, and the ICR value for fluoroanil. The TCT method has been applied to more than 200 molecules. About 30 have been determined by the HPMS and ICR methods and many have been confirmed by the ECD method. Many have also been confirmed by the half-wave reduction potential method and/or solution charge transfer complex spectra. These will be discussed in Chapter 10. The colli-sional ionization method of measuring relative electron affinities can produce inverted orders of intensities and give excited-state Ea rather than ground-state Ea. 

ELECTRON AFFINITIES DETERMINED USING THE MAGNETRON, ALKALI METAL BEAM, PHOTON, AND COLLISIONAL IONIZATION METHODS... 

Electron Affinities Determined Using the Magnetron Method... 

Electron Affinities Determined Using Photon Methods... 

ELECTRON AFFINITIES DETERMINED USING ECD, NIMS, AND TCT METHODS 245... 

Explain how ionization energy and electron affinity determine whether elements will combine to form ionic compounds. 

Such calculations were used historically to determine electron affinities after the enthalpies for the other reactions had been either measured or calculated. The improved experimental accuracy of modem electron affinity determinations permits these cycles to provide even more accurate lattice enthalpies. Despite the simplicity of this approach, it can be powerful in calculating thermodynamic properties for reactions that are difficult to measure directly. 

In aprotic nonaqueous media, the organic electrochemistry of anodic and cathodic reactions is concerned predominantly with radical-ion chemistry in many cases involving aromatic substances, the radicals are of sufficient stability for them to be characterized spectroscopically by conventional absorption spectrophotometry and by esr spectroscopy. Linear relations are found between the cathodic and anodic half-wave potentials and the ionization potentials or electron affinities determined in the gas phase. The oxidation and reduction potentials can also be related to the theoretically calculated energies of the highest occupied (anodic process) or lowest vacant (cathodic process) molecular orbitals. 

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