Effect of correlation on the elastic scattering of slow positrons from molecules
Abstract
Many-body correlation plays a crucial role in the low-energy positron-molecule scattering dynamics. In the present work, we have integrated a recent model correlation potential, developed by Swann and Gribakin, with the single-center expansion method and verified its efficacy in reproducing the best of ab initio and experimental results, for both non-polar and polar molecules. Starting with the already tested molecules-hydrogen, ethylene, and acetylene with the model correlation, we extended our calculations to oxygen-containing molecules: oxygen, water, and formic acid. In order to provide a comparative study, we have also performed calculations employing the model correlation of Perdew and Zunger. Integral, differential, and momentum transfer cross sections are reported for the target molecules. Positron virtual/bound state formation is also predicted using both of the model correlations. Overall, an improved agreement of our results with the literature for the recent model suggests the approach can be employed for larger systems, where the ab initio techniques are difficult to implement.