Background-free inelastic-scattering spectra were measured for even-$A$ neodymium (Nd) isotopes using a halo-free 386-MeV $\alpha$ beam at forward angles, including $0^{\circ }$, to examine the influence of deformation on isoscalar giant resonances. The strength distributions of isoscalar giant resonances (with multipolarity $L\le 3$) in ${}^{142}\mathrm{Nd}$ and ${}^{146-150}\mathrm{Nd}$ isotopes are determined using multipole decomposition analysis. This analysis is based on angular distributions calculated within the framework of the distorted-wave Born approximation with transition densities generated with a Woods-Saxon type potential. The isoscalar giant monopole resonance exhibits a distinct splitting into low-energy and high-energy components while going from the spherical nucleus ${}^{142}\mathrm{Nd}$ to the well-deformed nucleus ${}^{150}\mathrm{Nd}$ due to coupling with the $K=0$ component of the isoscalar giant quadrupole resonance (ISGQR). The isoscalar giant dipole resonance displays a bimodal structure, with an evidence of coupling between the dipole ($E1$) and high-energy octupole ($E3$) resonance due to deformation effects. The ISGQR splits into distinct $K$ components ($K=0$, 1, and 2) due to deformation. A signature of an overtone mode in ISGQR at an energy around 26 MeV has been obtained.

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• Collective levels
• Giant resonances
• Inelastic scattering reactions
• Resonance reactions