After the PLS reaction has reached 3 MC1, the further reaction proceeds via IC to other MCs. In the second step, we observe an elongation with rotation in Re-COax (R1) bond as it transitions to 3 MC2 via 3 TS2 with a small frequency of 75i, in this step we observe a small elongation in the main process in PLS reactions i.e., R1 bond change is 0.19 Å. In the third step, we observe a stretch Re-COax bond as it transitions to 3 MC3 via 3 TS3 a huge frequency of 657i, in this step we observe an elongation in R1 bond change is 0.22 Å. The fourth step, we observe a rotation in CO-ligand as it transitions to 3 MC4 via 3 TS4 a small frequency of 52i, in this step we observe a nominal contraction in R1 bond of 0.04 Å. In the final step, we observe an elongation with rotation in Re-COax (R1) bond as it transitions to 3 MC5 via 3 TS5 with a frequency of 127i, in this step we observe a rotation and a huge elongation in the main process in PLS reaction i.e., R1 bond change of 0.87 Å. Another important change in the 3 MC5 geometry is the bending of Re-COeq (R3) bond towards Re-COax (R1) bond which eventually pushes away the dissociative CO-ligand. After transitioning to 3 MC 5 , the system transitions into the dissociative 1/3 MECP region as the singlet and triplet energy on the triplet geometries of all the 3 MCs decreases continuously as we move from 3 MC1 to 3 MC5, as shown in Table . Once the system has reached in the dissociative 1/3 MECP region, the system jumps into singlet state as Re-COax (R1) bond is only elongated in the singlet state which eventually leads to the formation of singlet adduct, as discussed in the next section, while staying in the triplet state is repulsive and never reaches the dissociative 1/3 MECP region as shown in Figure .