The $2^+$ strength functions

Figures 3 and 4 show similar results as Figs. 1 and 2, but for the $2^+$ strength functions in $^{132}{\rm Sn}$. As for the $0^+$ case, the IS and IV strength functions from the Arnoldi iteration agree very well with the strength functions of Ref. [17]. The convergence of strength functions is as fast as for $0^+$; after $120$ iterations the smoothed strength functions change only by about $5\%$. We thus have to make only $120$ iterations to calculate reasonably accurate $2^+$ strength functions for the RPA problem whose dimension is $D=1020$. The large double spikes observed in Fig. 4 below 10MeV are due to the lowest RPA phonons, which by the smoothing procedure acquire $\simeq$100-keV widths and move slightly down in excitation energy.

Figure 3: Similar to Fig. 1 but for the $2^+$ strength functions. All results were calculated for the SLy4 functional.

Figure 4: Similar to Fig. 2 but for the $2^+$ strength functions.