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THE SHAPE TRANSITION IN ROTATING NUCLEI
F. Ivanyuk1, K. Pomorski2 and J.Bartel3
1Institut for Nuclear Research, Kiev, Ukraine2Theoretical Physics Division, UMCS, Lublin, Poland3Institute Pluridisciplinaire Hubert Curien, Strasbourg University, Strasbourg, France
• Introduction• The Strutinsky‘s procedure for the shape of
fissioning nuclei• The shape transition in axially symmetric
rotating charged liquid drop• The shape of triaxial rotating drop• Summary and outlook
Strutinsky‘s optimal shapes
( ) profile function
LD LD surf Coul curvE E E E
z
E
2
1
2
1
2surf
22
Coul
2 ( ) 1 ( / )
1 ( )( ) ( , ( ))
2
z
z
z
LD Sz
E z d dz dz
d zE x z z z dz
dz
21 2 12 12
20, ( )LDE V R R z z dz
V
2 2 3/2
1 2
(0) (0) 2the fissility parameter, / 2 ( / ) / 49
( ) the Coulomb pot
1 ( ) 10 ( ) (
ential on the surf
1 ( )
ce
)
a
LD S
LD LD C S
S
x x E E
x
z
z
A
z
Z
V.M.Strutinsky et al, Nucl. Phys. 46, 659 (1963)
(z)
z
Optimal shapes of fissioning drop
-2 -1 0 1 2
-1
0
1
xLD
=0.75
(z)
/R0
z / R0
The deformation energy
xLD
=1.0
xLD
=0.0
1.0 1.5 2.0 2.5-0.1
0.0
0.1
0.2
0.3
E
def /
E(0
) surf
R12
/ R0
F. Ivanyuk, Int. J. Mod. Phys. E18 (2009) 130
The shape of axially symmetric rotating drop
1 2 12var .principle : 0 0LD LD rotE V R E V E
2 2 2
:
/ 2 , ( / ) rigid-bodymoment of i
theenerg
ert
y
n ia
RLD surf Coul curv rot
rot
E E E E E
E L J J M V r dV
h
J. Bartel, F. Ivanyuk and K.Pomorski, Int. Jour. Mod. Phys. E19 (2010) 601
2 2 2 3/2
(0) (0) (0)
2 2
2
/ , ( ) / , /
( ) 2 , for the perpendicular rotation
2 ( ) , for the par
151 ( )
d
10 ( )
allel rotat
( ) (1 ( ) )
iff.equ
ion
4
ation
LD rot S rot rot rot rot
LD S
rot
rot LD rot
y E E z
x z B y z
B B E E
z z
z
( ) {rot z
The energy and shape transition in axially symmetric rotating drop
( 1) 2 ( 1) ( 1)RLD surf LD Coul LD rotB B x B y B
0.0 0.2 0.4 0.6-0.15
-0.10
-0.05
0.00
'perpendicular' rotation 'parallel' rotation
xLD
=0
BR
LD
0.0 0.1 0.2 0.3 0.4-0.10
-0.05
0.00
xLD
=0.25
0.00 0.05 0.10 0.15 0.20
-0.04
-0.02
0.00 xLD
=0.50
BR
LD
yLD
0.00 0.01 0.02 0.03 0.04 0.05
-0.004
-0.002
0.000x
LD=0.75
yLD
The deformation energy of rotating drop
0.5 1.0 1.5 2.0
0.00
0.01
0.02
0.03
0.04
0.05
yLD
=0.04
yLD
=0
xLD
=0.75E
defLD
M+
Ero
t
R12
/ R0
The energy and shape transition in axially symmetric rotating drop
( 1) 2 ( 1) ( 1)RLD surf LD Coul LD rotB B x B y B
0.0 0.2 0.4 0.6-0.15
-0.10
-0.05
0.00
'perpendicular' rotation 'parallel' rotation
xLD
=0
BR
LD
0.0 0.1 0.2 0.3 0.4-0.10
-0.05
0.00
xLD
=0.25
0.00 0.05 0.10 0.15 0.20
-0.04
-0.02
0.00 xLD
=0.50
BR
LD
yLD
0.00 0.01 0.02 0.03 0.04 0.05
-0.004
-0.002
0.000x
LD=0.75
yLD
The shape transition in rotating drop
-1 0 10.0
0.5
1.0
z / R0
'perpendicular' rotation 'paralel' rotation
xLD
=0.5, yLD
=0.124
(z)
/ R
0
-1 0 10.0
0.5
1.0
xLD
=0.25, yLD
=0.225
(z)
/ R
0
The energy and shape transition in axially symmetric rotating drop
( 1) 2 ( 1) ( 1)RLD surf LD Coul LD rotB B x B y B
0.0 0.2 0.4 0.6-0.15
-0.10
-0.05
0.00
'perpendicular' rotation 'parallel' rotation
xLD
=0
BR
LD
0.0 0.1 0.2 0.3 0.4-0.10
-0.05
0.00
xLD
=0.25
0.00 0.05 0.10 0.15 0.20
-0.04
-0.02
0.00 xLD
=0.50
BR
LD
yLD
0.00 0.01 0.02 0.03 0.04 0.05
-0.004
-0.002
0.000x
LD=0.75
yLD
The critical rotational velocities
-1 0 1
-1
0
1
(
z) /
R0
z / R0
0.0 0.5 1.00
1
2
3
0.612
ycr
it
x
The non-axial rotating drops
K. Pomorski, F. Ivanyuk and J. Bartel, Acta Phys. Polon. B42 (2011) 455 A. May, K. Mazurek, J. Dudec, M. Kmiecik and D. Rouvel, Int. J. Mod. Phys. E19 (2010) 532
2
2
22
2 22
( ) ( , ), ( , , ; , )
Euler-Lagrange equation: 0
Fourier series: ( , ) ( )cos( )
Approximations: ( , ) ( )[1 ( )cos(2 )]
(1 / ) 1( , )
1 cos(2( ,
)
RLD z
z
n
n
z z E dz d z
d d
dz d
z z n
z
z
z z
z cz
2( ) 1 ( ))
1 ( ) cos(2 )
z z
z
The equations for ( ) and ( )z z
2 2 2 21 2 3 4 5 6
23 2
2 2 2 21 2 3 4 5 6
2
2
15 51 (1 )[2 ] ( ) 0,
216
2
15 51 (1 )( ) 0
2 216
LD
LD
LDSa
rot
LDSb
rot
a a a a a a
y xz z
B
b b b b b b
y xz
B
2 2
20 0
( , ) [ ( ) cos(2 )] ( , )( ) , ( )
2 1 ( )cos(2 ) 2 [1 ( )cos(2 )]S S
Sa Sbz z zd d
z zz z
21 , ( , ) theCoulombpotentialon thesurfaceS z
The shape of axially non-symmetric rotating drop
-1 0 10.0
0.5
1.0
xLD
=0.75
yLD
=0.043
yLD
=0
(z
) / R
02
-1 0 10.0
0.5
1.0
yLD
=0.044
yLD
=0.01
-1 0 1
0.0
0.1
0.2
(z)
z / R0
-1 0 1
0.0
0.1
0.2
z / R0
The energy of axially non-symmetric rotating drop
0.00 0.05 0.10 0.15 0.20-0.05
-0.04
-0.03
-0.02
-0.01
0.00
0.01
'perpendicular' rotation 'parallel' rotation nonaxial 'perp.' rotation
xLD
=0.5
B
RLD
yLD
The energy of axially non-symmetric rotating drop
0.00 0.01 0.02 0.03 0.04 0.05-0.004
-0.003
-0.002
-0.001
0.000
0.001
'perpendicular' rotation 'parallel' rotation nonaxial 'perp.' rotation
xLD
=0.75
B
RLD
yLD
The comparison with ellipsoidal shapes
0.0 0.1 0.2
1
2 xLD
=0.5
sem
i-axe
s
yLD
22 2 22
2 2 2
( ) 1 ( )1(dash), ( , ) (solid)
1 ( ) cos(2 )
z zx y zz
za b c
The effective ellipsoids
0.0 0.1 0.2
1
2
3
xLD
=0.5
sem
i-axe
s
yLD
2 220 20
.
2 222 22
.
( , ) ( , ) ,
( , ) ( , )
ellips optimal
ellips optimal
r Y r Y
r Y r Y
The effective ellipsoids, the energy
2 220 20
.
2 222 22
.
( , ) ( , ) ,
( , ) ( , )
ellips optimal
ellips optimal
r Y r Y
r Y r Y
0.00 0.05 0.10 0.15 0.20-0.05
-0.04
-0.03
-0.02
-0.01
0.00
0.01
xLD
=0.5
BR
LD
yLD
triaxial ellipsoides nonaxial 'perpendicular' rotation
The limiting values of rotational velocity
0.00 0.25 0.50 0.75 1.000.0
0.2
0.4
0.6
0.8
ymax, fission
yJac.
xLD
y max
0 100 200 3000
25
50
75
100
ymax, fission, axial
L max
A
Summary and outlook
• Within a liqiud drop model we have developed a method for the calculation of optimal shape of the surface within a broad region of rotational velocitiy and fissility parameter
• We have found out that sharp Jacobi transition from oblate to triaxiall ellipsoides is the result of limitation imposed by the assumption of the ellipsoidal shape
• For the more flexible shape parmeterisation the Jacobi transition gets smoothed
• For the drops with the fissility parameter xLD>0.612 the fission takes place before the Jacobi transition
• The investigation of Poincare instability will be the subject of future studies
Thank you for attention
The barrier heights, topographical theorem
28 30 32 34 36 380
10
20
30
barr
ier
heig
ht (
MeV
)
Z2 / A
Bexp
BLSD
-Emicr
(gs)
(saddle) (saddle) (g.s.) (g.s)B LSD LSDV =E +δE -E +δE
W. D.Myers and W. J. Swiatecki, Nucl. Phys. A601, 141 (1996): the “barrierwill be determined by a path that avoids positive shell effects and has no use for negative shell effects. Hence the saddle point energy will be close to what it would have been in the absence of shell effects, i.e., close to the value given by the macroscopic theory!”
(saddle)B LSD micr
(g.s) (g.s.) (sph)micr LSD LSD
V =V +E ,
E =δE +(E -E )
F.A.Ivanyuk and K.Pomorski, Phys: Rev. C 79, 054327 (2009)