Effects of nuclear orientation on the mass distribution of fission fragments in the reaction of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">S</mml:mi><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>36</mml:mn></mml:mrow></mml:mmultiscripts><mml:mo>+</mml:mo><mml:mmultiscripts><mml:mi mathvariant="normal">U</mml:mi><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>238</mml:mn></mml:mrow></mml:mmultiscripts></mml:math>

Fragment mass distributions for fission after full momentum transfer were measured for the reaction $^{36}\mathrm{S}+^{238}\mathrm{U}$ at bombarding energies around the Coulomb barrier. The data revealed a transition from symmetry to asymmetry mass distributions when the beam energies were decreased from above-barrier to sub-barrier values. The main components of the asymmetric mass distribution are at ${A}_{\mathrm{H}}\ensuremath{\approx}200$ and ${A}_{\mathrm{L}}\ensuremath{\approx}74$. The asymmetric fission is attributed to quasifission of the reacting system at polar collisions, whereas the symmetric fission originates from the compound nucleus produced in equatorial collisions. The results suggest a strong influence of orientation effects of the deformed target nuclei on fusion.

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