Vertical affinity

Since some gas-phase values for the affinity of these systems for electrons or other negative ions are lacking, analogous schemes for the corresponding anions arc still incomplete. Preliminary vertical affinities, /l(C2H4) = —1-78 0-1, EACCzHz) = - 2-9+ 0-2 eV ,. (CjH) = 2-50 01 and (C,H3)> 1-27 eV , as well as... 

Fig. 37.4. Spectral map of the 26 opioid agonists and antagonists in 4 receptor binding tests, as described by Table 37.7 [45, 46]. Circles refer to the compounds. Squares represent the binding tests. Areas of circles and squares are proportional to the marginal mean affinities in the table. The lines that join the three poles (DHM, DADLE and EKC) of the map represent axes of contrast between the p-, 8-and K-opioid receptors. The horizontal and vertical components represent 18 and 79%, respectively, of the interaction in the data.

The vertical ionization potential of the electron donor is represented by Ip, and the electron affinity of the acceptor by E. ... 

H. Han, M. B. Zimmt, Solvent-Mediated Electron Transfer - Correlation Between Coupling Magnitude and Solvent Vertical Electron Affinity , J. Am. Chem Soc 1998,120, 8001-8002. 

Using the fact that the energy is linear with respect to the number of electrons and Janak s theorem [31], the orbital energies of the N—n and N+n electron system become equal to the exact ground state vertical ionization energy and electron affinity, respectively ... 

FIGURE 34.3 Correlation of the vertical electron affinity, calculated using Equation 34.36 at the PBE/aug-cc-pVTZ level, with experimental values. All values are in eV data are taken from Table 34.3. (Reprinted from De Proft, F., Sablon, N., Tozer, D.J., and Geerlings, P., Faraday Discuss., 135, 151, 2007. With permission.)... 

Our implementation computes only vertical ionization energies and electron affinities, but experimental results for the G2 species are adiabatic. To facilitate a direct comparison between the theoretical and experimental results, it is necessary that either the theoretical results be corrected to adiabatic values or that the adiabatic values be related to vertical ones. We have chosen the latter approach and have corrected the experimental results with computational data. 

Transitions between anions and neutral species were also calculated with two procedures. In the first, we calculated the vertical P3 electron affinities of neutral species. The experimental adiabatic electron affinities of the neutral molecules were shifted according to... 

Electron affinities were calculated as described above with the vertical corrections applied to the experimental results. For molecules with electron affinity data, the overall results are good, with a MAD of just 0.20 eV. The F atom was difficult to describe and this failure is probably related to the low accuracy of the CF2 calculation, where the error exceeded 1.0 eV. 

The test set used for most comparisons in the present paper is Database/3 18), which was introduced elsewhere. It consists of 109 atomization energies (AEs), 44 forward and reverse reaction barrier heights (BHs) of 22 reactions, 13 electron affinities (EAs), and 13 ionization potentials (IPs). There are a total of 513 bonds among the 109 molecules used for AEs, where double or triple bonds are only counted as a single bond. Note that all ionization potentials and electron affinities are adiabatic (not vertical), i.e., the geometry is optimized for the ions... 

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