電気的に励起された 岩田順敬 ( 東大理 ) Cedric Simenel (CEA/Saclay) 原子核の時間発展 Thanks to: 大塚孝治 ( 東大理、東大 CNS 、理研 ) Michael Bender (CEA/Saclay)

Electric excitation for fissions tar get E1 excitation E2 excitation Electric excitation Induced fission Real time evolution Photo-induced fission

Let us break 16 O ! Ideas for “The way of giving some energies for the ground state”  Induced fission (electrical excited initial state) TDHF TDHF (with excitation) Full Diabatic E2 excitation E1 excitation  Deformed initial state Constraint HF + TDHF + Adiabatic J. W. Negele et al., Phys. Rev. C. 17, 3 (1978) Initial state on the saddle point

Interaction TDHF Lagrangian → One body evolution Antisymmetrized potential TDHF equation (←Time dependent variational principle) TDHF Equation with Excitations Electric excitation SLy 4d SLy4d : SLy4d : Chabanat - Bonche - Hansel, (1995)

AmplitudeTime t 0 Instantaneous Time-orderingExcitation part ”One body time evolution” (final form) Electric Excitations ( E1 & E2 Excitation ) : Hamiltonian with nuclear force

The initial state HF ground state we calculate the HF ground state of Oxygen 16 E2 excitation E1 excitation time “The boundary condition” is chosen to be Dirichlet zero on the edge of 3D box The initial and the boundary value problem for TDHF equation Ev8 : P. Bonche et al., Comp. Phys. Com. 171, 49 (2005) P. Bonche et al., Comp. Phys. Com. 171, 49 (2005) space

E2 excitation The most dominant transition in each case is considered to be as follows: Energy E2 excitation causes deformation Excited initial state (small amp. & GQR dominance) Time evolution Q 2 oscillation E2 excitation

Excitation energy: 16MeV The lower and the upper energy estimate for the induced fission energy of quadrupole type E2 excitati on Nonlinearity exists: a small difference in excitation leads a large difference ! Gap 262MeV 288MeV 86MeV 22MeV 16 O 1 time step = 0.45 fm/c

E2 excitati on 192MeV fission oscillation 288MeV time = fm/c 16 O 8 Be + 8 Be

E1 excitation Two mode coupling state We will measure the deformation by The most dominant transition in each case is considered to be as follows: Energy E1 excitation also causes deformation Time evolution Q 2 oscillation Important state of this case C. Simenel and Ph. Chomaz. Phys. Review C, 68. (2003) ． E1 excitation

The exchange of the dominant excitation for [fm 2 ] E* [MeV] q0q0 E1 excitation: E2 excitation: Initial state trivial R b/a 2b/a 2 16 O 15MeV E1 E2 Small amp. b/ab/a

TDHF Results of Electric Oscillation caused by E1 excitation 16 O E1 Excitation (18MeV) is given evolution

Existence of a singular point 16 O 157MeV 274MeV 71MeV 18MeV 423MeV ~800MeV E1 excitati on Singular point is observed in TDHF calculation There exists a singular point around here More precisely, 242MeV –309MeV

TDHF Results of Electric Oscillations Center of oscillation Damping oscillation def E1 excitati on critical 16 O 274MeV 424MeV 157MeV 71MeV 605MeV Converging to excited oxygen Separating into fragments At the critical At the critical, “Dominant transition exchange” is switched on !? damped oscillation Above the critical, damped oscillation can be seen in motion.

E1 excitati on 274MeV Broken Excited state 605MeV time = fm/c

CHF calculation for 16 O ~35MeV Q 2 Constraint is given

CHF result for the initial state of TDHF calculation Real time evolution TDHF How about the dynamics of the fission fragment ? 35MeV Excited state with 35MeV from the ground state CHF time = fm/c time = 0.0 fm/s

Summary E1 excitation E1 excitation Perspective “unstable nuclei” Based on this result, we will go for “unstable nuclei” E2 excitation E2 excitation CHF + TDHF calculation CHF + TDHF calculation 280MeV ( 17.5 MeV/A ) 35MeV 35MeV + adiabatic (initial state) full diabatic Excitation energy [MeV] 280~ O Exchange of E1 & E2 CHF Induced fission(TDHF) Diff.profile for E1 & E2 gaposcillation or not