Description of positron-hydrogen resonances using the stochastic variational method

The complex scaling method combined with the stochastic variational approach has been used to calculate the energy and widths of a number of L=0 resonant states of the positron-hydrogen system. The interparticle correlation functions reveal evidence of cluster formation in the resonance state. The lowest L=0 resonance associated with the H(n=2) threshold shows a bulge in the e(-)-e(+) correlation function located at the same distance as the probability maximum of the Ps(1s) state.