Effects of 2 particle–2 hole configurations on dipole states in neutron-rich $N$ = 80–84 isotones

International audienceStarting from the Skyrme interaction SLy4 we study the effects of 2 particle–2 hole configurations on the low-energy electric dipole response in$^{130–134}$Sn. It is shown that the pygmy dipole resonance properties are correlated with the neutron skin thickness. The two-phonon configurations give a considerable contribution to the low-lying E1 strength