1. Supplementary material for: Formation Pathways of MSEA from DMS-OH in the Presence of O 2 : A Theoretical Study JUAN M. RAMÍREZ-ANGUITA, ÀNGELS GONZÁLEZ-LAFONT*, JOSÉ M. LLUCH Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain

2. C1 C2 C3 C4 Figure S1. Geometries of the MPW1K/MG3S minima corresponding to the different conformations for the radical CH 3 S(O 2 )(OH)CH 3. Distances are given in Å. Angles are given in degrees.

3. SP12 SP41 SP34 SP23 Figure S2. Geometries of the MPW1K/MG3S saddle points which connect two conformations of the radical CH 3 S(O 2 )(OH)CH 3. Distances are given in Å. Dihedrals are given in degrees.

4. -5.0 -4.0 -3.0 -2.0 0.0 1.0 2.0 C1 -1.3 C2 -1.3 C3 -4.4 C4 -4.2 SP12 1.6 SP23 0.6 SP34 -1.5 SP41 -0.3 C1 -1.3 DMSOH + O 2 0.0 Figure S3. Gibbs free energy profile at the CCSD(T)/MG3S//MPW1K/MG3S level for the stationary points of the exchange process of the different CH 3 S(O 2 )(OH)CH 3 conformations. Energies are given in kcal/mol. Table S1. Energies of the stationary points for the exchange process of the CH 3 S(O 2 )(OH)CH 3 conformations at different levels of calculation. V and _ stand for the classical potential energies and the adiabatic potential energies, respectively. All energies (in kcal/mol) are relative to DMS-OH + O 2.

5. SP4-1a Figure S4. Geometries of the MPW1K/MG3S stationary points located for the reaction R4. Distances are given in Å. Dihedrals are given in degrees.

6. SP4-1b

7. Min4-1

8. SPMin4

9. Min4-2

10. SP4-2

11. PC4-1

12. SP4-3

13. PC1/PC4-2

14. -30 -20 -10 0 10 20 30 40 Min2a 8.2 Min2b 6.9 SP4-1a 26.4 SP4-1b 24.5 Min4-2 -5.4 Min4-1 -7.4 SPMin4 2.5 PC4-2 -16.8 SP4-3 29.1 SP4-2 14.8 PC4-1 -3.8 MSEA + CH 2 OOH -5.8 MSEA + CH 3 OO -18.8 O 2 + DMSOH 0.0 Figure S5. CCSD(T)/MG3S/MPW1K/MG3S Gibbs free energy (kcal/mol) profile at 298 K for the reaction R4

15. Table S2. Energies of the stationary points for the reaction R4 at different levels of calculation. V and stand for the classical potential energies and the adiabatic potential energies, respectively. All energies (in kcal/mol) are relative to reactants.

16. SP5 Figure S6. Geometries of the MPW1K/MG3S stationary points located for the reaction R5. Distances are given in Å. Dihedrals are given in degrees.

17. PC5