is fragmented over many 1p1h states by the Landau damping, and strength in each 1p1h state is further spread due to the coupling with 2p2h states. Let us evaluate the spreading width $\gamma_{12}$ of the 1p1h states due to this coupling. We shall also evaluate the spreading width $\gamma_{22}$ of 2p2h states, which is caused by the residual coupling among 2p2h states.

![ Averaged strength function of (a) TD states and (b) 2p2h states. Average was performed over levels lying in 9 MeV - 13 MeV. The number of levels is 12 and 3342 for TD states and 2p2h states, respectively. []{data-label="fig_avedoorstr"}](fig11.eps){width="9.2cm"}

We evaluate $\gamma_{12}$ by using the strength functions of TD states as in Ref. [@aiba2]. Namely, we calculate the strength function of each TD state. Averaging the strength functions over whole TD states, we obtain Fig. \[fig\_avedoorstr\] (a). The FWHM of this averaged strength function gives an evaluation of the spreading width $\gamma_{12}$. We read $\gamma_{12 }=0.38$ MeV. (Note that we define $\gamma_{12 }$ as the spreading width of TD states instead of that of unperturbed 1p1h states.) The value of spreading width of 2p2h states $\gamma_{22}$ is also evaluated in the same manner. From Fig. \[fig\_avedoorstr\] (b) 