On the rotational temperature and structure dependence of electric field deflection experiments: A case study of germanium clusters

Molecular beam electric field deflection experiments offer a probe to the structural and dielectric properties of isolated particles in the gas phase. However, their quantitative interpretation is still a formidable task. Despite the benefits of this method, the analysis of the deflection behavior is often complicated by various experimental and theoretical problems, including the amount of energy stored in internal and rotational modes of the deflected particle and the amount of structural asymmetry. In this contribution, we address these issues by discussing the experimentally observed field-induced deflection of Ge-9, Ge-10, and Ge-15 clusters in comparison to quantum mechanical and classical deflection models. Additionally, we derive simple formulas to describe how the molecular beam deflection depends on the rotational temperature and the symmetry of the particle. Based on these results, we discuss to what extend molecular beam electric field deflection experiments can be used as a tool for structure determination of isolated clusters in the gas phase. (C) 2011 American Institute of Physics. [doi:10.1063/1.3610390]