We study the role of colliding geometry on the N/Z dependence of balance energy using isospin-dependent quantum molecular dynamics model. Our study reveals that the N/Z dependence of balance energy becomes much steeper for peripheral collisions as compared to the central collisions. We also study the effect of system mass on the impact parameter dependence of N/Z dependence of balance energy. The study shows that lighter systems shows greater sensitivity to colliding geometry towards the N/Z dependence.
Using the quantum molecular dynamics model, we study the role of mass asymmetry of colliding nuclei on the fragmentation at the balance energy and on its mass dependence. The study is done by keeping the total mass of the system fixed as 40, 80, 160, and 240 and by varying the mass asymmetry of the ($eta$ = $frac{A_{T}-A_{P}}{A_{T}+A_{P}}$; where $A_{T}$ and $A_{P}$ are the masses of the target and projectile, respectively) reaction from 0.1 to 0.7. Our results clearly indicate a sizeable effect of the mass asymmetry on the multiplicity of various fragments. The mass asymmetry dependence of various fragments is found to increase with increase in total system mass (except for heavy mass fragments). Similar to symmetric reactions, a power law system mass dependence of various fragment multiplicities is also found to exit for large asymmetries.
Using the isospin-dependent quantum molecular dynamics model we study the isospin effects on the disappearance of flow for the reactions of 58Ni+58Ni and 58Fe+58Fe as a function of impact parameter. We found good agreement between our calculations and experimentally measured energy of vanishing flow at all colliding geometries. Our calculations reproduce the experimental data within 5%(10%) at central (peripheral) colliding geometries.
Using the quantum molecular dynamics model, we study the nuclear dynamics at the balance energy of mass asymmetric colliding nuclei by keeping the total mass of the system fixed as 40, 80, 160, and 240. The calculations are performed by varying the mass asymmetry ($eta$ = $frac{A_{T}-A_{P}}{A_{T}+A_{P}}$; where $A_{T}$ and $A_{P}$ are the masses of the target and projectile, respectively) of the reaction from 0.1 to 0.7. In particular, we study the various quantities like average and maximum density, collision rate, participant-spectator matter, anisotropic ratio, relative momentum as well as their mass asymmetry and mass dependence. We find sizeable effects of mass asymmetry on these quantities. Our results indicate that the mass dependence of various quantities increases slightly with increase in $eta$.
We present a systematic study of disappearance of flow i.e. balance energy $E_{bal}$ for an isotopic series of Ca with N/Z varying from 1 to 2 for different density dependences of symmetry energies. We also extend this study for asymmetric reactions having radioactive projectile and stable target.