Reactive Scattering

Question 1

experimental measurement

Answer 1

crossed molecular beams or laser photolysis

Question 2

reaction cross section

Answer 2

fraction of total cross section that gives a reaction

Question 3

dependence of reaction cross section on collision energy on reactions with a barrier

Answer 3

steady increase from threshold energy then levels off at higher collisional energy

Question 4

dependence of reaction cross section on collision energy for reactions without a barrier

Answer 4

no threshold energy, generally large reaction cross section and declines from max at collision energy = 0

Question 5

lines-of-centres model

Answer 5

only motion along the line-of-centres (ie reaction coord) is effective in crossing the barrier

Question 6

why does line-of-centres break down at higher collisional energy

Answer 6

model assumes the combined centrifugal and intrinsic barrier is fixed at r=d, not true at higher collision energies/large b and not applicable to reactions without a barrier