Electron Affinities and Periodic Trends of Homonuclear Diatomic Molecules

1 Electron Affinities and Periodic Trends of Homonuclear Diatomic Molecules 

The electron affinities of the main group homonuclear diatomic anions have been measured by PES. A few experimental values for the transition metal dimers are also available. The electron affinities of all the 3d homonuclear diatomic molecules have been calculated using density functional methods [1-4], Only the AEa of I2, 2.524 eV C2, 3.27 Si2, 2.2o S2, 1.67 F2, 3.0g Cl2, 2.4s Br2, 2.5, and 02, 1.07 have been measured by more than one method [1-3]. CURES-EC calculations confirm these to within 0.1 eV. Positive excited states Ea have been measured for 02, C2, and I2 and are inferred for other X2 [5-8]. Just as in the case of the atomic Ea, the trends in the Periodic Table can support the assignments of AEa for the other elements. 

2 Electron Affinities and Morse Potential Energy Curves  

As early as the 1960s D. R. Herschbach calculated six Morse curves for I2(—). The data used to calculate these curves were described as follows  

Electron impact experiments only show that that the curves for some states of X2(—) 

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