Can a single ammonia and water molecule enhance the formation of methanimine under tropospheric conditions?: kinetics of •CH2NH2 + O2 (+NH3/H2O)

The aminomethyl (•CH 2 NH ) radical is generated from the photo-oxidation of methylamine in troposphere and an important precursor for new particle formation. effect ammonia water on gas-phase formation methanimine (CH NH) • CH + O reaction not known. Therefore, this study, potential energy surfaces (+NH 3 /H O) were constructed using ab initio //DFT, i.e., coupled - cluster theory (CCSD(T))//hybrid-density functional theory, M06-2X with 6-311++G (3df, 3pd) basis set. Rice−Ramsperger−Kassel−Marcus (RRKM)/master equation (ME) simulation Eckart’s asymmetric tunneling was used to calculate rate coefficients branching fractions relevant troposphere. results show 40% at low-pressure (<1 bar) 100% OO high-pressure limit (HPL) condition. When molecule introduced into reaction, there a slight increase NH; however, when ∼80%. calculated coefficient [1.9 × 10 −23 cm −1 s ] (+H [3.3 -17 -1 least twelve six order magnitudes smaller than those free (2 −11 298 K) reactions, respectively. Our result consistent that previous experimental theoretical analysis good agreement its isoelectronic analogous reaction. work also provides clear understanding tropospheric carcinogenic compounds, hydrogen cyanide (HCN).