A <transition state> is the configuration or dividing-surface region associated with passage between reactant and product basins. In the elementary saddle-point picture it is a first-order saddle of the <potential energy surface>: stable against small displacements in transverse directions but unstable along the reaction direction. <Transition state theory> counts forward crossings and, in its simplest form, neglects recrossing.

Solution

Past exam of the chemistry A course of the University of Cambridge / 2025 / Paper 2 / A8 / a / iii / Solution

 Solution (source code)