  Using the complex scaling and the stabilization method combined with the
stochastic variational approach, we have shown that there are narrow resonance
states in two-dimensional three particle systems of electrons and holes
interacting via screened Coulomb interaction. These resonances are loosely
bound systems of excited state excitons with a third particle circling around
them. Recent experimental studies of excited state trions might be explained
and identified by these resonant states.
