Mv. Vener et Vg. Mairanovskii, DISSOCIATIVE ELECTRON-TRANSFER - GAS-PHASE MODEL WITH PREDISSOCIATIONMINIMUM (GM-MODEL) - CONSIDERATION BY AM1 METHOD, Russian journal of electrochemistry, 29(10), 1993, pp. 1084-1089
The quantum-chemical method AMI was first used for investigating the p
rocesses of gas-phase dissociative electron transfer (DET) to the mole
cules of alkyl halides RX. The investigated alkyl halides encompassed
chlorine, bromine, and iodine derivatives, as well as polyhalogenated
compounds. The AM1 method was found to yield realistic results that ag
ree with experimental data. According to the postulate of the GM-model
(the gas-phase model with a predissociation minimum) that was suggest
ed earlier, a predissociation minimum for most of the radical anions [
R-X]radical anion was detected on the potential energy curve. By makin
g the AM1 calculation, the effective activation energies of electron t
ransfer (E(ae)), the bond rupture in the radical anion (E(ar)), and t
he values of intramolecular energy of reorganization lambda(i) were es
timated. Certain regularities resulting from the GM-model were establi
shed. These are: the E(ae) decrease in the series X Cl > Br > I; the
intibate change in the activation energies E(ae) and E(ar); and the l
inear relationship between force constants f and f of the R-X bond in
the starting molecule and radical anions, with f' invariably less than
f.