Higher-lying resonances in Ps-H scattering below thee+-H−threshold

In this work, we perform a study on high-lying $S$-wave resonances in Ps-H scattering below the ${e}^{+}$-H${}^{\ensuremath{-}}$ threshold. The method of complex-coordinate rotation is applied together with highly correlated wave functions containing all six interparticle distances. Using such Hylleraas bases up to 6412 terms, the energy positions up to the 8$S$ state and the widths up to the 7$S$ state in the Rydberg series converging to the H${}^{\ensuremath{-}}$ threshold are determined. The energies of 4$S$ to 7$S$ states from the present calculations are fitted into the quantum defect formula, from which the energies of higher members in the Rydberg series can be deduced.