Journal of Physical Chemistry A, Vol.108, No.23, 5069-5072, 2004
Thermal electron attachment to chloroalkanes and Herschbach ionic morse potentials for carbon tetrachloride (CCl4)
New rate constants for thermal electron attachment to chloroalkanes were measured in a recent swarm ionization cell study (Barszczewska, W.; Kopyra, J.; Wnorowska, J; Szamrej, I J. Phys. Chem. A 2003, 107, 11427). Electron affinities of haloakanes were calculated and used to construct one ionic potential energy curve to model the electron attachment process. Six of the 11 summary items presented should be revisited based on the following results and published complementary studies. The adiabatic electron affinity of CCl4 is calculated using the MNDO CURES-EC approach to be 2.2 eV in agreement with experiment. The Feynman, Lesk, Herschbach, Wentworth hypotheses place a lower limit of zero on the long-range electron affinity, the adiabatic electron affinity, and the anion dissociation energy in a given bond dimension. Eight ionic Morse potential energy curves for CCl4(-) are calculated using the Herschbach classifications and experimental or predicted metrics. The antibonding, a, and bonding, b, curves are a two-dimensional cut through the multidimensional surface in which the geometry of the leaving groups are fixed. The X curve allows for rearrangement while the "c" curves are in a third electron-molecule dimension.