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

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Chapter 6 In most reactions studied in chapter 3 [35] the diabatic potential has a minimum in the neck parameter ε around ε = 0.65—0.85. Due to the large inertia and friction coefficient in the neck coordinate ε obtained in chapter 5 [43], the DNS configurations with fixed neck parameters have a long lifetime in comparison to the reaction time. In contrast to the Ref. [42], where the fusion probability through the fission-type valley with small ε was considered, fusion probabilities P CN obtained for fixed large ε depend correctly on the initial value <strong>of</strong> η in the entrance channel [34]. As in Ref. [42], the adiabatic treatment <strong>of</strong> fusion in λ yields fusion probabilities which are considerably overestimated in comparison to the experimental data although a fixed large neck ε is considered. The reason <strong>of</strong> this overestimate is clearly seen in Fig. 6-1, where the adiabatic potentials for different fragmentations leading to the same compound nucleus 246 Fm are shown as a function <strong>of</strong> λ at ε = 0.75. In contrast to experiment the hindrance <strong>of</strong> fusion in these potentials is practically absent (P CN ≈ 1) because there is no fusion barrier for the motion to smaller elongations λ. The diabatic effects in the entrance phase <strong>of</strong> the collision studied in chapter 3 strongly hinder the motion <strong>of</strong> the system to smaller elongations λ. The study <strong>of</strong> the transition from the diabatic potential to the adiabatic one in the motion <strong>of</strong> the system in λ during the lifetime <strong>of</strong> the dinuclear system allows us to conclude whether the fusion is possible in the elongation coordinate. 81
V (MeV) 30 25 20 15 10 5 0 -5 -10 110Pd+ 136Xe 86Kr+ 160Gd 76Ge+ 170Er 1,2 1,3 1,4 1,5 1,6 1,7 1,8 6-1: Adiabatic potentials as a function <strong>of</strong> λ calculated within the TCSM for differ- Figure combinations leading to the same compound nucleus ent 246 The nuclei are considered as Fm. spherical and the neck parameter ε =0.75. The crosses denote the touching configurations. 82 λ
Page 1 and 2:
Effects of
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1 Introduction 6 1.1 The DNS-concep
Page 5 and 6:
Chapter 1 The elements existing in
Page 7 and 8:
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
Page 17 and 18:
higher collective velocities to rep
Page 19 and 20:
2.1 General considerations We want
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couplings. Diabatic basis states ψ
Page 23 and 24:
Chapter 3 The synthesis of<
Page 25 and 26:
is calculated within the TCSM using
Page 27 and 28:
E adiab (MeV) n E diab (MeV) n 30 2
Page 29 and 30: E diab (MeV) n 60 55 50 45 40 100Mo
Page 31 and 32: 3-5: Diabatic potentials for the sy
Page 33 and 34: 3-7: The same as in Fig. 3-6 for th
Page 35 and 36: The estimated collective velocities
Page 37 and 38: 3-10: Diabatic contributions as a f
Page 39 and 40: effects give a justification for th
Page 41 and 42: The similarity of
Page 43 and 44: 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: ~ f k (MeV -1) 0,20 0,15 0,10 0,05
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 and 96: The value of t0 is
Page 97 and 98: Y Z Y A 0,10 0,08 0,06 0,04 0,02 0,
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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Effects of diabaticity on fusion of heavy nuclei in the dinuclear model ...

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