Quasi-elastic and massive transfer reactions in the ${}^{16}\mathrm{O}+{}^{89}\mathrm{Y}$ reaction at beam energies around ≈4–5 MeV/nucleon

Kinetic energy spectra, angular distributions, and cross sections of projectilelike fragments (PLFs) with $Z_{\mathrm{PLF}}=3-7$ have been measured in ${}^{16}\mathrm{O}+{}^{89}\mathrm{Y}$ reaction at $E_{\mathrm{lab}}=62.2$, 73.4, 78.5, and 83.5 MeV respectively. Comparison of angular distributions of PLFs, particularly of nitrogen (N), at different beam energies showed increasing contribution from overlapping collision trajectories at higher beam energies. Angular distributions of PLFs became more forward peaked with the amount of mass transfer indicating an increasing overlap of the projectile and the target nuclei with increasing mass transfer. PLF cross sections could be reasonably explained by the modified sum-rule model except for carbon (C) indicating the role of alpha cluster structure of ${}^{16}\mathrm{O}$ nucleus in the transfer process. Large cross section for PLF emitted in the α transfer channel in ${}^{16}\mathrm{O}+{}^{89}\mathrm{Y}$ reaction compared to that in ${}^{19}\mathrm{F}+{}^{89}\mathrm{Y}$ reaction further supported this observation.

Figure 1

Plot of elastic scattering data at different beam energies for ${}^{16}\mathrm{O}+{}^{89}\mathrm{Y}$ system. Solid lines are fit to the data using the code SNOOPY 8Q [33]. Grazing angle values in center of mass frame of reference are given in the figure. The values inside the bracket are corresponding beam energies.

Figure 2

Angular distribution of different projectilelike fragments (PLFs) formed in ${}^{16}\mathrm{O}+{}^{89}\mathrm{Y}$ reaction at various beam energies. In each panel, arrows from right to left mark the grazing angles corresponding to $E_{\mathrm{lab}}=62.2$, 73.4, and 83.5 MeV respectively.

Figure 3

Cross sections of projectilelike fragments in ${}^{16}\mathrm{O}+{}^{89}\mathrm{Y}$ reaction at $E_{\mathrm{lab}}=62.2$ MeV (a), 73.4 MeV (b), 78.5 MeV (c), and 83.5 MeV (d). Abscissa represents amount of charge transferred $\left(Z_{\mathrm{trans}}\right)$. Bars are labeled with the corresponding PLFs. Filled bars are the experimental data (light grey: cross section corresponding to the angular range covered in the measurement; dark grey: cross section obtained by extrapolation/fitting). Bars with pattern (slanting lines) are the results of modified sum-rule model calculations. The parameter $T$ and $F_{\mathrm{T}}$ obtained from the fit are also given in the figure (see text for details).

Figure 4

Comparison of cross sections of projectilelike fragments (PLFs) from ${}^{16}\mathrm{O}+{}^{89}\mathrm{Y}$ and ${}^{19}\mathrm{F}+{}^{89}\mathrm{Y}$ reactions, plotted as a function of $E_{\mathrm{c}.\mathrm{m}.}/V_{\mathrm{b}}$. Cross sections corresponding to the different amount of charge transfer $\left(Z_{\mathrm{trans}}\right)$ are shown in different panels. Evaporation residue data for $Z_{\mathrm{trans}}=2$ from Ref. [32] are also shown in the figure.