Laura McCaslin

Laura McCaslin
Laura McCaslin
Zuckerman Postdoctoral Scholar (alum) Laura McCaslin publishes paper in ChemPhysChem
The Hebrew University of Jerusalem

Paper abstract:

The reaction of N2O5 at atmospheric interfaces has recently received considerable attention due to its importance in atmospheric chemistry. N2O5 reacts preferentially with Cl to form ClNO2/NO3 (Cl substitution), but can also react with H2O to form 2HNO3 (hydrolysis). In this paper, we explore these competing reactions in a theoretical study of the clusters N2O5/Cl/nH2O (n=2–5), resulting in the identification of three reaction motifs. First, we uncovered an SN2-type Cl substitution reaction of N2O5 that occurs very quickly due to low barriers to reaction. Second, we found a low-lying pathway to hydrolysis via a ClNO2 intermediate (two-step hydrolysis). Finally, we found a direct hydrolysis pathway where H2O attacks N2O5 (one-step hydrolysis). We find that Cl substitution is the fastest reaction in every cluster. Between one-step and two-step hydrolysis, we find that one-step hydrolysis barriers are lower, making two-step hydrolysis (via ClNO2 intermediate) likely only when concentrations of Cl are high.