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A general nonparameterized continuum scattered wave (CMS) method for calculating total and differential elastic cross sections for electron-molecule scattering at low energies (0-30 eV) is presented. The method uses a local exchange approximation based on the Hara free electron gas model. The parameters required for exchange potential and the energy-dependent polarization potential are generated entirely within the calculation. CMS results for argon and methane are presented. The argon results compare very favorably with results recently obtained from an ab-initio R-matrix method. At very low energies the results agree very well with recent experimental work for the scattering length and the position and magnitude of the Ramsauer-Townsend minima observed for both argon and methane. An analysis of the potential suggests that the Slater transition-state half-occupation method used to generate the scattering potential could be a way of automatically including both a self-interaction correction and a weak correlation-polarization term similar to that obtained from the accurate electron gas correlation expression of Ceperly and Alder.

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The structural response of Dy2TiO5 oxide under swift heavy ion irradiation (2.2 GeV Au ions) was studied over a range of structural length scales utilizing neutron total scattering experiments. Refinement of diffraction data confirms that the long-range orthorhombic structure is susceptible to ion beam-induced amorphization with limited crystalline fraction remaining after irradiation to 8 × 1012 ions/cm2. In contrast, the local atomic arrangement, examined through pair distribution function analysis, shows only subtle changes after irradiation and is still described best by the original orthorhombic structural model. A comparison to Dy2Ti2O7 pyrochlore oxide under the same irradiation conditions reveals a different behavior: while the dysprosium titanate pyrochlore is more radiation resistant over the long-range with smaller degree of amorphization as compared to Dy2TiO5, the former involves more local atomic rearrangements, best described by a pyrochlore-to-weberite-type transformation. These results highlight the importance of short-range and medium-range order analysis for a comprehensive description of radiation behavior.

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