Tables of Evaluated Electron Affinities

TABLE A1.2 Main Group Homonuclear Diatomic Molecules (in eV)  

The electron affinities of the Group II homonuclear diatomic molecules should be greater than the electron affinity of the atom. 

National Institute of Standards and Technology (NIST). Chemistry WebBook, 2003. Available at http //webbook.nist.gov. 

Blondel, C. Delsart, C. and Goldfarb, F. J. Phys. B—Atom. Molec. Opt. Phys., 2001, 34, L281. 

Feldman, D. In Proc. 8th Intern. Conf. on Electr. Atom. Collis, Belgrade, 1973. 

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TABLE 10.6 Evaluated Electron Affinities (in eV) of Hydrocarbons Using the ECD Method [57]... 

The tables in Appendix IV summarize the evaluated values of the electron affinities given in this book. The electron affinities of the atoms and homonuclear diatomic molecules are given in two tables, Al.l and A1.2. The references for both tables are combined. The electron affinities of the hydrocarbons are given in Tables A2.1 and Al.l. Tables A2.3 and A2.4 provide the electron affinities of the halogenated hydrocarbons. The odd-numbered tables are ordered by value and the even-numbered tables are ordered by molecular weight. The references for the hydrocarbons are given separately from those of the CHX compounds. Tables A3.1 and A3.2 list the values for the CHNX molecules. These were combined because there are so few halogenated compounds. Tables A4.1 and A4.2 contain the electron affinities of the CHO and CHOX compounds, while Tables A5.1 and A5.2 contain those of the CHON and CHONX compounds. 

Table 2.2 Comparison of W2 and W1 theories, and their variants for the evaluation of electron affinity and ionization potential (eV) for selected species from G2-1 test set.

A substantial body of data exists evaluating the utility of DFT (and other methods) for computing ionization potentials and electron affinities following a ASCF approach. These data are summarized over four different test sets in Table 8.4. The conclusions one may... 

The initial Hiickel calculations can be employed to obtain preliminary values for the electron densities and bond orders, from which the self-consistent field matrix elements can be evaluated by introduction of the chosen core potentials and electron repulsion integrals.11 Table I lists the ionization potentials, electron affinities and nuclear charges employed in the present calculations. 

MOyi) Ij. and Zg are the ionization potential of the rth AO in the valence state and the effective core charge of the sth AO,respectively. One center Coulomb repulsion integrals (rrlrr)=Ij.-Ej,(Ei. is the electron affinity of the rth AO in the valence state), the values of which adopted in this paper are collected in Table 1 with the values Ij.. Two center Coulomb repulsion integral are evaluated by the for-... 

Table 4.3 lists AAG values, the ECD Ea, and the Ea from 1/2, of several aromatic hydrocarbons obtained in this manner. The electron affinity for pentacene was determined by TCT, while that of coronene is the value obtained from reduction potentials [6]. The Ea are verified using CURES-EC. The calculated values are given in Table 4.3. Also listed are the weighted average of the values that cluster about the current evaluated values from a 1983 compilation [27]. The consistency of the Ea values in this table support the gas phase experiment and the assignments of lower values to excited states.

Figure 8.2 Electron affinities of the elements in the form of a Periodic Table. The values in parentheses are the uncertainties in the last figure. The other statistics are given with their proper number of significant figures. The dates are those of the determination or selection as the evaluated values [10-17].

The electron affinities of all the SF from n 0 to 7 have been measured or calculated theoretically. The NIST tables contain the Ea for many of these compounds, but do not assign or evaluate them. A. E. S. Miller and coworkers evaluated the available ground-state values but did not consider excited states [106]. The assignment of Ea for SF6 to excited states was used in Chapter 5 as an example. The ground-state value is 1.07 0.07 eV, and excited-state values are 0.75, 0.5, 0.3, and 0.0 eV. 

The electron affinities of organic halides and environmental pollutants are evaluated in Chapter 11 and those of biological molecules in Chapter 12. Many of the Ea measured in the gas phase are tabulated in the NIST tables [1], These are listed in the appendices according to molecules containing CHX, CHNX, CHOX, and CHONX with references. The ECD values for some of the aromatic hydrocarbons in NIST have not been updated. L. G. Christophorou s compilation includes Ea from half-wave reduction potentials and charge transfer complexes [2]. Some of these Ea will be revised and evaluated in this chapter based on gas phase measurements. 

The electron affinities of the alkyl and cycloalkyl halides reported in the NIST tables are tabulated and evaluated in Appendix II. The NIST value is returned by a sequential search, using CX, CC1F, or CHX. In some cases two values that differ by more than the uncertainty have been reported so excited-state values can be assigned. Many of the Ea have only been measured by one technique thus, the experimental values could refer to an excited state. 

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