Vertical electron detachment

V.V. Zakjevskii et al., Electron propagator studies of vertical electron detachment energies and isomerism in purinic deoxyribonucleotides. Int. J. Quantum Chem. 107, 2266-2273 (2007)... 

Table 5 8 3. Experimental and calculated vertical electron detachment energies (VDEs, in kJ mol 1) for LiAl, NaAl, and CuAl ...

We calculate the enthalpy of formation at 0 K as the difference between a H"(PF, g, OK) = -8.55 5.0 kcal mol" (1 ) and the selected value of 1.1 0.5 eV (25.366 kcal mol" ) for the electron affinity (EA) of PF. The value of EA refers to the vertical electron detachment process PF"(g) = PF(g) + e" and is taken from the molecular orbital study of O Hare 2). This value was obtained from Hartree-Fock energies and estimated corrections for correlation effects. The estimated uncertainty in EA is 0.5 eV which should be adequate to cover the possibility that the adiabatic value is lower than the vertical EA. Other theoretical predictions of EA include 2.55 eV ( ) and 1.4 eV (4). 

Tab. 17.1. The relative stability, vertical electron detachment energy, binding energy of CO (with O2 preadsorbed) and binding energy of O2 (with CO preadsorbed) for the five structures (a)-(e) ofAu2C03, shown in Figure 17.2C.

Table 4 Vertical electron-detachment energies (in eV), with different approximations, along the reaction path...

TaF5 and TaFxCl5 x have been identified in the gas phase by mass spectrometric detection of their primary ions.220 The crystal structure of the salt [Ph3PMe][TaF6] has been reported.403 The gas-phase molecular structure, vibrational frequencies, and vertical electron detachment energy for [rl aF6] were examined theoretically at HF, MP2, and DFT levels of theory.404... 

Fig. 1.16. The graph presents a comparison of theoretical and experimental vertical electron detachment energies (VDEs) for Aun in = 4-14). The optimized ground state structures (labeled A for each size) and close lying low-energy isomers are also displayed [120]. A change from planar geometry to SD-structural motifs is apparent between Aui2 and Auis ...

As an illustration consider C=C=C=C which is a triplet ( Sg ) with a -It HOMO occupied by two electrons of parallel spin. Table 21 displays results obtained with several different levels of correlation and basis sets." There are actually three different quantities that can be computed the vertical electron detachment energy (VEDE, energy to eject electron at the geometry of the anion) the adiabatic electron affinity (AEA, when the neutral M is allowed to relax to its optimum geometry), and the vertical electron affinity (VEA, where the geometry of the neutral is assumed for the anion). 

TTie vertical electron detachment energy (VDE) is calculated as the total energy difference between the anionic and neutral clusters, both taken in the anionic optimized geometry without die ZPVE. The adiabatic electron affinity (EAa) and ionization energy (lEa) are calculated as the total energy difference between the anionic and cationic clusters, respectively, and the parent neutral cluster in their optimized geometries. 

In early applications of the jellium model, the shape of metal clusters was assumed in all instances to be spherical [33, 34], but soon it became apparent that the spherical symmetry was too restrictive [35, 36]. Indeed clusters with open electronic shells (between the magic numbers = 2, 8, 20, 40, 58, 92, etc.) are subjected to Jahn-Teller distortions [37]. By now it has been well established that a quantitative description of the underlying shell effects and of fragmentation phenomena (as well as of other less complicated phenomena such as ionization and vertical electron detachment) requires a proper description of the deformed shapes of both parent and daughter clusters (of both precursor and final ionic or neutral product in the case of ionization and vertical electron detachment). 

The ensemble of initial conditions can be characterized by the Franck-Condon transition probabilities and visualized in terms of the abundances of the vertical electron detachment energies (VDE s) between the Ag4 and Ag species. The histograms of the VDE s for three ensembles of different temperatures are shown in Fig. 7. For the ensemble generated for T=50 K,... 

Fig. 5.6. One-dimensional cuts of the PESs of the ground states of Ag, Ags, and Ag along Qr = — (Qx) + QyY for fixed values of the polar angle a = arctan(Qx/Qy) = 120° and Qs = 2.81 A(by courtesy of M. Hartmann, taken from [136]). Qs, Qx, and Qy correspond to the symmetric stretching, the bending, and the antisymmetric stretching coordinate of the AgJ cation, respectively. The chosen Qs value is that of the neutral s equilibrium nuclear configuration. The vertical electron detachment energy is 2.45 eV, the vertical ionization energy for the linear transition state and the equilibrium geometry of the neutral are 6.67 eV and 5.73 eV, respectively. The dashed line is the first excited electronic state of Ags...

FIGURE 13.2 Free-energy curves A(jr) of the reduced (R) and oxidized speeies (O) plotted against an unspeeified reaction coordinate x. Nonequilibrium states created by vertical electron detachment (oxidation) or attachment (reduction) are marked by a superscript. The corresponding energy level scheme is indicated on the right. 

As the title of this chapter suggests, the discussion here is limited, for the most part, to loosely bound electrons, meaning that valence ionization is not considered to any significant extent. It is important to keep in mind, however, that loosely-bound need not mean weakly-bound. As mentioned earlier, vertical electron detachment energies in excess of 1-2 eV are possible even... 

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