Close to converged energies and expectation values for e+He(Se3) are computed using a ground state wave function consisting of 1500 explicitly correlated Gaussians. The best estimate of the e+He(Se3) energy was -2.25059508hartree, which has a binding energy of 0.00059508hartree against dissociation into Ps+He+. The 2? annihilation rate for the spin doublet state was 5.713�09s-1. The estimated annihilation rate with the core He+ electron was 2.506�06s-1. The derived enhancement factor for annihilation with the He+(1s) core was 2.29, just over 10% smaller than the enhancement factor derived from analyses of annihilation during e+-He+ scattering. The diffuse nature of the wave function, with well separated He+ and Ps subsystems, is demonstarted to be on the threshold of satisfying the formal criteria that define a quantum halo state. � 2005 The American Physical Society.
|Number of pages||6|
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|Publication status||Published - 2005|