In this article the calculations of the activation free energy for a chemical reaction between styrene-7,8-oxide and DNA, in particular guanine at position N7, are reported. Calculations were performed
by Hartree-Fock and DFT methods in conjunction with flexible basis sets. Effects of solvation were considered using the Langevin dipoles method. The calculated activation free energies are in good agreement with the experimental value of 26.52 kcal mol−1
