The 27th International Conference on Atomic Physics

Confined variational calculation of low energy Ps-Li+ scattering

Not scheduled

1h 30m

Abstract of recent or ongoing work (by remote / virtual participant) Atomic, molecular, and charged-particle collisions Abstracts by remote participants

Description

Interactions of positron and positronium (Ps) with atoms and ions have been extensively studied in recent years, with great attention being paid to the formation of weakly bound states of positronic complexes [1,2], the collision and electron-positron annihilation processes [3]. However, accurate $\mathit{\text{ab initio}}$ description of these systems is challenging due to the complicated short-range correlations among particles. Utilizing the gradient-based optimization method [4,5] and the stochastic variational method (SVM) [6,7] with $4200$ explicit correlated Gaussian (ECG) basis functions, we obtained the nonrelativistic energy $-7.53241063$ hartree for the ground state of Ps-Li${}^{+}$(${}^{1}S$), which has improved the previous value $-7.53241048$ hartree obtained by Bubin et al. [1] with $3000$ ECGs. This improvement demonstrated that our program of the gradient-based optimization of ECGs’ nonlinear parameters is correct and efficient. Therefore, the low energy Ps-Li${}^{+}$ elastic scattering is studied with the confined variational method (CVM) developed by Mitroy et al. [8,9] and the gradient-based optimization method.

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