Electronic Effects on Reactivity

Question 1

covalent-ionic curve crossing

Answer 1

ionic and covalent curve cross at Rx = crossing radius, at distances < Rx the ionic curve is lower in energy, if system switches from covalent to ionic at Rx there’s very strong attraction, ions accelerate rapidly towards each other and react giving a harpoon mechanism

Question 2

harpoon mechnism

Answer 2

neutral atom transfers e- to more electronegative neutral atom, forms ions, strong coulombic attraction draws ions together and forms new bond

Question 3

for harpoon mechanism, why does reaction cross section decrease with increasing translational energy

Answer 3

faster trajectories at large impact parameters only slightly < Rx won’t be drawn in enough by the attractive potential therefore they recross the boundary and reactants escape

Question 4

electronically induced reactivity

Answer 4

produces excimers

Question 5

for multisurface reactions

Answer 5

need to convert electronic symmetry

Question 6

why do some intermediates have a long lifetime

Answer 6

energy randomised between vibrational modes