Effects of anharmonic vibration on large-angle quasi-elastic scattering of 16O+144Sm

TL;DR

This study investigates how anharmonic vibrations in 144Sm influence large-angle quasi-elastic scattering of 16O, using coupled-channels calculations that include anharmonic effects, to better match experimental data.

Contribution

It introduces an explicit inclusion of anharmonic vibrational effects in coupled-channels calculations for quasi-elastic scattering, improving the understanding of nuclear excitation influences.

Findings

Experimental quasi-elastic cross sections are well reproduced.

The quasi-elastic barrier distribution shows a high energy peak that is smeared experimentally.

Standard coupled-channels approach cannot simultaneously explain fusion and quasi-elastic barrier distributions.

Abstract

We study the effects of double octupole and quadrupole phonon excitations in the 144Sm nucleus on quasi-elastic 16O+144Sm scattering at backward angles. To this end, we use the coupled-channels framework, taking into account explicitly the anharmonicities of the vibrations. We use the same coupling scheme as that previously employed to explain the experimental data of sub-barrier fusion cross sections for the same system. We show that the experimental data for the quasi-elastic cross sections are well reproduced in this way, although the quasi-elastic barrier distribution has a distinct high energy peak which is somewhat smeared in the experimental barrier distribution. We also discuss the effects of proton transfer on the quasi-elastic barrier distribution. Our study indicates that the fusion and quasi-elastic barrier distributions for this system cannot be accounted for simultaneously with the standard coupled-channels approach.