Collision frequency

Main article: Collision theory

Collision frequency is defined in chemical kinetics, in the background of theoretical kinetics, as the average number of collisions between reacting molecules per unit of time per moles of reactant. Its symbol is Z. For a gas-phase bimolecular reaction, Z is

$Z = N_A \sigma_{AB} \sqrt \frac{8 k_B T}{\pi \mu_{AB}}$

• N_A is Avogadro's number
• σ_AB is the reaction cross section
• k_B is Boltzmann constant
• T is temperature in kelvin
• μ_AB is the reduced mass of the reactants

References

• IUPAC Goldbook definition of Collision Frequency