Production cross sections of 243-248No isotopes in fusion reactions

The production of No243-248 is investigated within the framework of the improved quantum molecular dynamical model incorporated with a statistical model. The calculated results of the( 48Ca + 208)Pb fusion reaction can reproduce the experimental data well. The impact parameter and the incident energy influence the fusion probability and the lifetime of the neck in fusion reaction process. Furthermore, the evaporation residue cross sections of Ca-40,Ca-44,Ca-48 +Pb-208, Ne-20 + U-233,U-235,U-238, O-16 +Pu-242, and Mg-26+Th-232 reactions are calculated. From investigation, the more neutrons there are in the projectile or target for the same projectile-target combination, the larger evaporation residue cross sections will be. Six unknown isotopes No243-248 are predicted with maximum evaporation residue cross sections 0.061 pb, 2.250 pb, 0.005 nb, 0.530 nb, 0.432 nb, and 3.518 nb, respectively. The corresponding fusion reactions are 208Pb(40Ca, 5n) No-243, Pb-208(40Ca, 4n) No-244, Pb-208(40Ca, 3n) 245No, Pb-208(40Ca, 2n)No-246, U-233(20Ne, 6n) No-247, and U-233(20Ne, 5n) 248No, respectively.