Diffuseness of the Nuclear Surface fromS-Wave Strength Functions

The $S$-wave strength function data is analyzed to find the diffuseness for the nuclei near $3S$ and $4S$ strength function giant resonances. The calculations are performed as a function of atomic weight, using a deformed optical-model potential for two values of the diffuseness parameter $a$ in the Saxon-Woods potential, $a=0.52\mathrm{}$ F and $a=0.30\mathrm{}$ F. The comparison of the data with the calculations indicates the value of $a$ to be (0.5±0.1) F, for the nuclei of both the $3S$ and $4S$ giant resonances. Our result for the $4S$ giant resonance is in disagreement with that of Vogt. The reason for the disagreement is discussed.