Photoionization energetics and dissociation pathways of hydroperoxyethyl formate produced in the reaction of CH3CHOO + formic acid

Abstract

The bimolecular reaction of Criegee intermediates, zwitterionic carbonyl oxide species produced in alkene ozonolysis, with organic acids leads to formation of functional hydroperoxides implicated in the generation of atmospheric aerosols. This theoretical study using high-level explicitly correlated coupled-cluster theory examines the low energy conformers of hydroperoxyethyl formate [HOOCH(CH3)OCHO, HPEF] formed in the bimolecular reaction of CH3CHOO, a simple alkyl-substituted Criegee intermediate, with formic acid, and the detection of HPEF via photoionization. The vertical and adiabatic ionization energies of HPEF are computed, along with the pathways for dissociative ionization that produce HO2 or OCHO fragments with daughter ions.