Impact of diffuseness parameter on nuclear potential depth and fusion barrier heights

Abstract The exact diffuseness parameter ( a ) is vital in fusion reactions as it determines nuclear potential shape, barrier height, and tunneling probability. Accurate a improves reaction cross-section predictions. Hence, the present study explores the impact of the diffuseness parameter ( a ) on nuclear potential depth ( V 0 ) and fusion barrier heights across 53 projectile-target pairs spanning a wide nuclear mass range with product of the atomic number range 224 ≤ Z 1 Z 2 ≤ 1116. By systematically varying a , we identified values that best match experimental barrier heights, revealing that larger a results in smoother potentials, lower fusion barriers, and increased fusion probabilities. We examined correlations between V 0 and entrance-channel parameters, finding that mean fissility ( χ m ) exhibited the strongest correlation ( R 2 = 0.875). A linear fit between V 0 a and χ m provided a predictive equation, emphasizing the role of fissility in fusion modeling. Optimized a values enabled accurate reproduction of total nuclear potentials, with heavier systems showing deeper potentials and hence higher fusion cross-sections. Comparisons with experimental data validated our approach, underscoring the importance of diffuseness parameter selection for improving theoretical fusion models.