Systematics of the giant monopole resonance from inelastic alpha scattering

Monopole strength inNi58

“…Inelastic alpha-scattering data on Ni were available [1,7] at nine angles from 0' to 8'. Additional data were taken at the crucial angles of 0' (where the EO strength is a maximum) and 4 (where EO is a minimum} as well as at 7, both to provide additional data for the fitting process and to increase confidence that the spectra were free from beam-related background.…”

“…Lui et al [4] reported 66%%uo of the EO energy-weighted sum rule (EWSR} in Si spread over an 8 MeV region, while Lu et al [5] reported 90% of the EO EWSR in Mg between 11 and 20 MeV. Approximately 30% of the EO EWSR was seen in ' Zn by Youngblood et al [1]. Duhamel et al [6], using small-angle inelastic alpha scattering, report 23%%uo of the EO EWSR 900 keV above the quadrupole in Ni, while in the small-angle inelastic scattering of Youngblood et al.…”

“…Duhamel et al [6], using small-angle inelastic alpha scattering, report 23%%uo of the EO EWSR 900 keV above the quadrupole in Ni, while in the small-angle inelastic scattering of Youngblood et al. [1] and further work of Garg et al [7], the monopole component in Ni was not identified. Bertrand et al [8] using inelastic proton scattering had earlier reported monopole strength at 20 MeV, which was not seen in the small-angle alpha scattering most sensitive to EO strength.…”

“…The isoscalar giant monopole resonance (GMR) is well established [1,2] at an excitation energy several MeV above the giant quadrupole resonance in nuclei with A~90. In lighter nuclei the monopole strength is located nearer the quadrupole (for Ca [3] and Si [4] at virtually the same energy). Only two reports of substantial strength in lighter nuclei are in the literature.…”

“…KXPKRINIENTAL Data analysis proceeded somewhat differently than reported in Refs. [1] and [7]. In those works, the continuum under the giant resonance was estimated by connecting points on either side of the peak with a smooth curve.…”