Transition State Theory — Activated Rate

Parameters

Temperature T (K): 300 Barrier ΔG‡ (kJ/mol): 50 ΔG_rxn (reaction free energy): -20 Pre-exponential A (×10¹²): 1.0

Rate Constants

k_forward: — s⁻¹

k_reverse: — s⁻¹

K_eq = k_f/k_r: —

Half-life t₁/₂: —

ΔΔG‡ (reverse): — kJ/mol

Theory

Eyring (1935): rate constant from partition functions of reactant and transition state:

k = (k_BT/h)·exp(ΔS‡/R)·exp(−ΔH‡/RT)

The Arrhenius plot (ln k vs 1/T) is a straight line with slope −Ea/R. Curvature indicates tunneling or temperature-dependent Ea. Marcus theory extends TST to electron transfer — parabolic free energy surfaces, inverted region.