89.6 Rate Theories of elementary reaction 9.6.2 Calculation of LaB Definition: collision cross-section S=Ta aB motionless AB ABADefinition:collision cross-section 2 S =dAB 2 Z AB =dAB V NB  A  A V NB motionless 9.6.2 Calculation of ZAB §9.6 Rate Theories of elementary reaction