Master Equation Studies of the Unimolecular Decay of Thermalized Methacrolein Oxide: The Impact of Atmospheric Conditions

Master equation simulations of the unimolecular reaction dynamics of the Criegee intermediate methacrolein oxide (MACR oxide) have been performed under a variety of temperature and pressure conditions. These simulations provide insight into how the unimolecular kinetics vary across temperatures spanning the range 288-320 K. This work has incorporated a new potential energy surface and includes the anti-to-syn and cis-to-trans conformational dynamics of MACR oxide, as well as the unimolecular reactions to form dioxirane and dioxole species. The competition between the unimolecular reactivity of MACR oxide and previously documented bimolecular reactivity of MACR oxide with water vapor is explored, focusing on how this competition is affected by changes in atmospheric conditions. The impact on the role of MACR oxide as an atmospheric oxidant of SO2 is noted.

Automated summary

Master equation simulations were conducted to study the unimolecular reaction dynamics of MACR oxide under different temperature and pressure conditions. The simulations revealed the temperature-dependent variation of the unimolecular kinetics in the range of 288-320 K. This work incorporated a new potential energy surface and considered the conformational dynamics as well as the formation of dioxirane and dioxole species. The competition between unimolecular reactivity and the previously documented bimolecular reactivity with water vapor was explored, with a focus on the influence of atmospheric conditions. The role of MACR oxide as an atmospheric oxidant of SO2 was also highlighted.