Effect of an Electric Field on the Structure and Stability of Atmospheric Clusters

We
study the influence of an applied electric field on
the structure
and stability of some common bimolecular clusters that are found in
the atmosphere. These clusters play an important role in new particle
formation (NPF). For low values of the electric field (i.e., |E| ≤ 0.01 V Å–1), we demonstrate
that the field response of the clusters can be predicted from simply
calculating the dipole moment of the cluster and the dipole moments
of the constituent molecules and that the influence on the association
energy of the cluster is minimal (i.e., <0.5 kcal mol–1). For higher field strengths |E| > 0.2 V Å–1, there can be more dramatic effects on both structure
and energetics, as the induced dipole, charge transfer, and geometric
distortion play a larger role. Although such large fields are not
very relevant in the atmosphere, they do exist in some situations
of experimental interest, such as near interfaces and in intense laser
fields.