There is an underlying continuum in the high excitation-energy region in the spectrum; it is reasonable to assume that this continuum, remaining after elimination of the instrumental background, is primarily due to contributions from excitation of the higher multipoles and quasifree knockout processes [44]. We have employed the MDA procedure [25] to extract the strengths of the isoscalar giant monopole resonance (ISGMR), the isoscalar giant dipole resonance (ISGDR), the isoscalar giant quadrupole resonance (ISGQR), and the high-energy octupole resonance (HEOR) in the Sn isotopes. The cross-section data were binned into 1-MeV energy intervals to reduce the statistical fluctuations. For each excitation energy bin from 8.5 MeV to 31.5 MeV, the experimental 17-point angular distribution dσ exp d Ω ( θ$_{cm}$, E$_{x}$ ) has been fitted by means of the least-square method with the linear combination of calculated distributions dσ cal L d Ω ( θ$_{cm}$, E$_{x}$ ) FIG. 3: Excitation-energy spectra obtained from inelastic α scattering at θ$_{lab}$ = 0.69 ◦ for all even-A Sn isotopes. III. DATA ANALYSIS 7 GLYPH<s49>GLYPH<s48> GLYPH<s50>GLYPH<s48> GLYPH<s51>GLYPH<s48> GLYPH<s48> GLYPH<s49>GLYPH<s48>GLYPH<s48> GLYPH<s48> GLYPH<s49>GLYPH<s48>GLYPH<s48> GLYPH<s48> GLYPH<s49>GLYPH<s48>GLYPH<s48> GLYPH<s48> GLYPH<s49>GLYPH<s48>GLYPH<s48> GLYPH<s48> GLYPH<s49>GLYPH<s48>GLYPH<s48> GLYPH<s48> GLYPH<s49>GLYPH<s48>GLYPH<s48> GLYPH<s48> GLYPH<s49>GLYPH<s48>GLYPH<s48> GLYPH<s49>GLYPH<s49>GLYPH<s50> GLYPH<s83>GLYPH<s110> GLYPH<s69> GLYPH<s120> GLYPH<s32>GLYPH<s40>GLYPH<s77>GLYPH<s101>GLYPH<s86>GLYPH<s41> GLYPH<s49>GLYPH<s49>GLYPH<s52> GLYPH<s83>GLYPH<s110> GLYPH<s49>GLYPH<s49>GLYPH<s54> GLYPH<s83>GLYPH<s110> GLYPH<s49>GLYPH<s49>GLYPH<s56> GLYPH<s83>GLYPH<s110> GLYPH<s100> GLYPH<s50> GLYPH<s100> GLYPH<s100> GLYPH<s40>GLYPH<s109>GLYPH<s98>GLYPH<s47>GLYPH<s115>GLYPH<s114>GLYPH<s77>GLYPH<s101>GLYPH<s86>GLYPH<s41> GLYPH<s49>GLYPH<s50>GLYPH<s48> GLYPH<s83>GLYPH<s110> GLYPH<s49>GLYPH<s50>GLYPH<s50> GLYPH<s83>GLYPH<s110> GLYPH<s49>GLYPH<s50>GLYPH<s52> GLYPH<s83>GLYPH<s110>