Comparison of OH(A–X) chemiluminescence spectra from photo-initiated intra-cluster reaction of HBr–N2O isomers prepared with He and Ar seeding gases

The internal energy distribution of product OH(A) was measured for the photo-initiated intra-cluster reaction of HBr–N2O prepared using either Ar or He seeding gas. We find that rotation of OH(A) produced from HBr–N2O seeded in Ar is more excited than that from HBr–N2O seeded in He. This difference could be ascribed to the difference in relative abundance of HBr–N2O geometric isomers in the cluster beam. The present result is consistent with the previous experimental finding in the focusing experiment of HBr–N2O using the electrostatic hexapole field, namely the preferential formation of the linear isomer under Ar seeding condition.