The structures of biomolecules, heteropolymers, and nanoclusters in gas phase backgrounds have been extensively studied through experimental drag-enhanced collision cross sections (CCS). In order to predict these gas phase structures, calculation techniques that mimic the momentum transfer process must therefore be employed. However, presently available techniques carry the underlying assumption that rigid models and specularly elastic collisions are a correct assumption under all circumstances. This belief clashes with many experimental observations using diatomic background gases, such as Nitrogen, Oxygen and Air, where gas molecule reemission appears to be inelastic and extremely diffuse rather than specular. This effect can be attributed to the energy exchange and impermanent state of structures and degrees of freedom (translational, rotational and vibrational). In this work, we will present a largely customizable interface where non-specular as well as specular gas molecule reemission rules can be invoked. Inherently focused on diatomic background gases, the interface allows one to choose between projection approximations, specular/diffuse, elastic/inelastic, trajectory methods involving polarizable molecules or diatomic molecules with Maxwell Rotational distributions.All these methods are analytically and computationally efficient, some being several tens to hundreds of times faster than other existing alternatives while dealing similar or better accuracy. This allows for calculations of tens of thousands of atoms without the need for parallelization. Several different experimental structure calculations will be presented along with the predictions and explanations of different methods.

Novel interfaced approach to mobility calculations with diffuse scattering and Maxwell rotational distributions for diatomic gases in the free molecular regime

246th National Meeting (2013)

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