Continuum QRPA in the coordinate space representation

We formulate a quasiparticle random phase approximation (QRPA) in the coordinate space representation. This model is a natural extension of the RPA model of Shlomo and Bertsch to open-shell nuclei in order to take into account pairing correlations together with the coupling to the continuum. We apply it to the Sn-120 nucleus and show that low-lying excitation modes are significantly influenced by the pairing effects although the effects are marginal in the giant resonance region. The dependence of the pairing effect on the parity of low-lying. collective mode is also discussed. (C) 2001 Elsevier Science B.V. All rights reserved.