Simulations of a polar molecule (sulfur dioxide) in a supersonic jet

Clustering of polar molecules (SO₂) in a supersonic jet was investigated by simulation. The cluster size N_c was calculated under different gas backing pressures P₀ and source temperatures T₀. Based on these results, the dependence of N_c on P₀ or T₀ was compared with that for the gases of non-polar molecules. It is found that SO₂ molecules condense very easily into clusters even when P₀ is very low. This result implies that large clusters can be produced using polar molecules, which could be useful in the studies of laser-cluster interactions. Also, SO₂ gas is an important component of air pollution, so the knowledge of the clustering properties of SO₂ could be helpful in the study of air pollution and environment.