Electronic energy, absolute

Figure 5.1 The parabolic distribution in energy, N(E), as function of energy, E, for free electrons. The Fermi surface represents the upper limit of electron energy at the absolute zero of temperature, but at higher temperatures a small fraction of the electrons can be excited to higher energy levels...

Electrode potentials are relative values because they are defined as the EMF of cells containing a reference electrode. A number of authors have attempted to define and measure absolute electrode potentials with respect to a universal reference system that does not contain a further metal-electrolyte interface. It has been demonstrated by J. E. B. Randles, A. N. Frumkin and B. B. Damaskin, and by S. Trasatti that a suitable reference system is an electron in a vacuum or in an inert gas at a suitable distance from the surface of the electrolyte (i.e. under similar conditions as those for measuring the contact potential of the metal-electrolyte system). In this way a reference system is obtained that is identical with that employed in solid-state physics for measuring the electronic energy of the bulk of a phase. 

Experimentally determined maximum absolute ionization cross sections for the inert gases and a range of small molecules are compared with the predictions of DM, BEB, and EM calculations in Table 1. Atomic orbital coefficients for the DM calculations were determined at the Hartree-Fock level and the EM cross sections are volume averaged for calculations carried out at the HF/6-31G level. Hie same data are plotted in Figure 5 with the calculated values on the ordinate and the experimental result on the abscissa. The heavy line represents a direct correspondence between experiment and theory. Although the ab initio EM method performs well for the calculation of qm and Em,T,17 the DM and BEB methods allow for the calculation of the cross section as a function of the electron energy, i.e. the ionization... 

Fig. 4-12. Electron energy levels in electron transfer from a standard gaseous electron throu an electrol3rte solution into an electrode a,(M/sn)) = real potential of electron in electrode E = electrode potential (absolute electrode potential).

Fig. 4-24. Electron energy levels for electrode potential relative to a reference electrode E = electrode potential (absolute) E = relative electrode potential Ps = outer potential of electrolyte solution of test electrode = outer potential of electrolyte solution of reference...

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