Reaction rate of H2CO (1A) and (3A) via TST.

In this work, we present the reaction rate and dissociation of formaldehyde H2CO, where we found three possible pathways for the singlet state (1A), and two for triplet state (3A). The optimized geometries and frequencies were determined at B3LYP/6-311g(2d,d,p) internal to CBS-QB3 methods. The reaction rates are calculated using the APUAMA code, applying the tunneling correction of Wigner, Eckart, and small curvature transmission coefficient (SCT), and the total reaction rate is presented in the Arrhenius form as [Formula: see text] and [Formula: see text], for singlet and triplet state, respectively. Graphical Abstract PES for singlet and triplet formaldehyde.