Effects of diabaticity on fusion of heavy nuclei in the dinuclear model ...

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7-2). In the reactions leading to the nuclei 286 112 and 292 114, the decay <strong>of</strong> the more symmetric DNS configurations becomes more pronounced. The motion <strong>of</strong> the initial DNS to more asym- metric configurations (mass asymmetry channel <strong>of</strong> fusion) in the reaction 48 Ca+ 208 Pb is more favourable than in the reactions 48 Ca+ 238 Uand 48 Ca+ 244 Pu, where the distributions show similar features for Z 48, around the nuclei 78 Zn and 32 Ge, respectively, for the light fragment with the corresponding heavy fragment 208 Pb. The height <strong>of</strong> this peak is 6 (3) times larger than the height <strong>of</strong> the peak in the symmetric mass region in the reaction 48 Ca+ 238 U ( 48 Ca+ 244 Pu). One can see that the results are in good agreement with the available experimental data, which were extracted from Ref.[11]. This experimental mass distribution includes the quasi-fission events in all angles measured. It should be noted that near the initial DNS configuration, the quasi-fission events overlapping with the products <strong>of</strong> other reaction channels (elastic and quasi-elastic peaks) were not taken into account in the experimental data because they cannot be clearly distinguish. In our calculations we assume that the DNS is formed in all reactions considered. In general, the formation <strong>of</strong> the DNS also depends on the capture probability, which is determined by the dynamical aspects <strong>of</strong> the approach stage <strong>of</strong> the reaction and by the depth <strong>of</strong> the pocket in the nucleus-nucleus interaction potential in the entrance channel [38]. The excitation energy <strong>of</strong> the initial DNS in all reactions considered is E ∗ =10 MeV and the lifetime t0 <strong>of</strong> the DNS is about (3 − 4)× 10 −20 s. The initial excitation energy E ∗ can be 97
Y Z Y A 0,10 0,08 0,06 0,04 0,02 0,00 0 0,10 10 20 Z 30 40 50 60 0,08 0,06 0,04 0,02 48Ca + 238U th. exp. 0,00 0 20 40 60 80 100 120 140 A 286112 E * = 5 MeV E * = 15 MeV 7-1: Charge (upper part) and mass (lower part) distributions <strong>of</strong> the quasi-fission products Figure a function <strong>of</strong> the charge Z and mass A numbers <strong>of</strong> the light fragments, respectively, for the as fusion reaction hot 48 + Ca 238 → U 286 The charge distribution is calculated for two values 112. the excitation energy <strong>of</strong> the initial DNS: E <strong>of</strong> ∗ (dotted line) and E =5MeV ∗ (solid =15MeV The mass distribution is compared with the experimental data [11] (open points) for line). E ∗ . =10MeV 98
Page 1 and 2:
Effects of
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1 Introduction 6 1.1 The DNS-concep
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Chapter 1 The elements existing in
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observed the rapid fall-of<
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Figure 1-1 illustrates the compound
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smaller than the extra-extra push e
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fusion and quasi-fission processes
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In the present chapter we have pres
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higher collective velocities to rep
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2.1 General considerations We want
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couplings. Diabatic basis states ψ
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Chapter 3 The synthesis of<
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is calculated within the TCSM using
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E adiab (MeV) n E diab (MeV) n 30 2
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E diab (MeV) n 60 55 50 45 40 100Mo
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3-5: Diabatic potentials for the sy
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3-7: The same as in Fig. 3-6 for th
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The estimated collective velocities
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3-10: Diabatic contributions as a f
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effects give a justification for th
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The similarity of
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4.1.3 Alternative microscopical met
Page 45 and 46: to the DNS concept [18, 34], cross
Page 47 and 48: U (MeV) 28 27 26 25 24 23 22 21 20
Page 49 and 50: U (MeV) 35 30 25 20 15 10 90Zr + 12
Page 51 and 52: 4-1: Fusion barriers B Table TCSM
Page 53 and 54: U (MeV) 40 30 20 10 20 10 0 a) b) 9
Page 55 and 56: experimental separation energy allo
Page 57 and 58: means a neglect of
Page 59 and 60: the case of an ind
Page 61 and 62: single particle density matrix exte
Page 63 and 64: following ratio in the limit <stron
Page 65 and 66: 5-1: Dependence of
Page 67 and 68: the microscopical mass parameter <s
Page 69 and 70: 5-3: Mass parameter Mεε as a func
Page 71 and 72: 5-4: Mass parameter Mεε as a func
Page 73 and 74: the approximate expressions (Eqs. (
Page 75 and 76: (10 3 m fm 2) M , M λλ εε 25 20
Page 77 and 78: (10 3 m fm 2) M εε M (10 λλ 4 m
Page 79 and 80: ~ f k (MeV -1) 0,20 0,15 0,10 0,05
Page 81 and 82: V (MeV) 30 25 20 15 10 5 0 -5 -10 1
Page 83 and 84: to the dependence of</stron
Page 85 and 86: where the lifetime t 0 of</
Page 87 and 88: 6-2: a) Time-dependent dynamical po
Page 89 and 90: Table 6-1: Quasi-fission and inner
Page 91 and 92: 6-3: Time-dependent average width <
Page 93 and 94: Chapter 7 In the quasi-fission proc
Page 95: The value of t0 is
Page 99 and 100: estimated from the difference betwe
Page 101 and 102: elements from Z=104 to Z=112 in the
Page 103 and 104: fission process is an important fac
Page 105 and 106: the neck coordinate ε and
Page 107 and 108: • The time-dependent transition b
Page 109 and 110: Appendix A For describing nucleus-n
Page 111 and 112: where The volume is V0 = 1 2 m0ϖ 2
Page 113 and 114: ϕ nz(z) = ⎧ ⎪⎨ ⎪⎩ C−1
Page 115 and 116: Appendix B The collective response
Page 117 and 118: [1] S.G.Nilsson et al., Phys. Lett.
Page 119 and 120: [27] N.V.Antonenko et al., in 1 st
Page 121 and 122: [63] Yu.F.Smirnov and Yu.M.Tchuvil
Page 123 and 124: [97] H. Hofmann et
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