Shell structure of the superheavy elements

doi:10.1016/S0375-9474(96)00337-5

Nuclear Physics A

Volume 611, Issues 2–3, 23 December 1996, Pages 211-246

https://doi.org/10.1016/S0375-9474(96)00337-5 Get rights and content

Abstract

Ground-state properties of the superheavy elements (SHE) with 108 ⩽ Z ⩽ 128 and 150 ⩽ N ⩽ 192 are investigated using both the Skyrem-Hartree-Fock method with a density-independent contact pairing interaction and the macroscopic-microscopic approach with an average Woods-Saxon potential and a monopole pairing interaction. Detailed analysis of binding energies, separation energies, shell effects, single-proton and neutron states, equilibrium deformations, Q_α-values, and other observables is given.

References (122)

K. Böning et al.
Z. Phys. A
(1986)
A. Sobiczewski et al.
Phys. Lett. B
(1987)
Z. Patyk et al.
Nucl. Phys. A
(1989)
S. Ćwiok et al.
Z. Phys. A
(1992)
Yu.A. Lazarev et al.
Phys. Rev. Lett.
(1994)
R. Smolańczuk et al.
Phys. Rev. C
(1995)
R. Bengtsson et al.
Phys. Scr.
(1984)
P. Möller et al.
Z. Phys. A
(1986)
P. Möller et al.
Nucl. Phys. A
(1992)
P. Möller et al.
At. Data Nucl. Data Tables
(1995)

Z. Patyk et al.

Nucl. Phys. A

(1989)

Z. Patyk et al.

Nucl. Phys. A

(1991)

P. Bonche et al.

Nucl. Phys. A

(1985)

J. Dobaczewski et al.

Phys. Scr.

(1995)

E. Chabanat et al.

Phys. Scr.

(1995)

J. Treiner et al.

Ann. Phys. (NY)

(1986)

Y. Nogami

Phys. Rev.

(1964)

H.C. Pradhan et al.

Nucl. Phys. A

(1973)

P. Möller et al.

Nucl. Phys. A

(1992)

A.S. Jensen et al.

Nucl. Phys. A

(1986)

W. Nazarewicz et al.

Phys. Scr.

(1995)

J. Dobaczewski et al.

Phys. Rev. Lett.

(1994)

V.M. Strutinsky

Nucl. Phys. A

(1967)

R. Bengtsson et al.

Z. Phys. A

(1989)

A. Sobiczewski et al.

Phys. Lett.

(1966)

G. Mairle

Z. Phys. A

(1995)

C.Y. Wong

Phys. Lett.

(1966)

C. Gustafson et al.

Ark. Fys.

(1967)

E. Rost

Phys. Lett. B

(1968)

U. Mosel et al.

Z. Phys.

(1969)

Yu.A. Muzychka

Phys. Lett. B

(1969)

T.A. Johansson

Nucl. Phys. A

(1972)

R.R. Chasman

Phys. Rev. Lett.

(1974)

A. Łukasiak et al.

Acta Phys. Pol. B

(1975)

P. Mukherjee et al.

Phys. Rev. Lett.

(1980)

W.H. Bassichis et al.

Phys. Rev. C

(1972)

G. Saunier et al.

Phys. Rev. C

(1972)

B. Rouben et al.

Phys. Lett. B

(1972)

M. Brack et al.

Phys. Scr. A

(1974)

R.Y. Cusson et al.

Phys. Rev. C

(1976)

F. Tondeur

Z. Phys. A

(1978)

F. Tondeur

Z. Phys. A

(1980)

F. Petrovich

S. Hofmann et al.

Z. Phys. A

(1995)

S. Hofmann et al.

Z. Phys. A

(1995)

S. Hofmann et al.

Z. Phys. A

(1996)

A. Ghiorso et al.

Nucl. Phys. A

(1995)

A. Ghiorso et al.

Phys. Rev. C

(1995)

Y.T. Oganessian

Nucl. Phys. A

(1995)

S. Ćwiok et al.

Nucl. Phys. A

(1983)

S. Ćwiok et al.

Nucl. Phys. A

(1985)

A. Sobiczewski et al.

Phys. Lett. B

(1989)

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Shell structure of the superheavy elements

Abstract

Z. Phys. A

Phys. Lett. B

Nucl. Phys. A

Z. Phys. A

Phys. Rev. Lett.

Phys. Rev. C

Phys. Scr.

Z. Phys. A

Nucl. Phys. A

At. Data Nucl. Data Tables

Nucl. Phys. A

Nucl. Phys. A

Nucl. Phys. A

Phys. Scr.

Phys. Scr.

Ann. Phys. (NY)

Phys. Rev.

Nucl. Phys. A

Nucl. Phys. A

Nucl. Phys. A

Phys. Scr.

Phys. Rev. Lett.

Nucl. Phys. A

Z. Phys. A

Phys. Lett.

Z. Phys. A

Phys. Lett.

Ark. Fys.

Phys. Lett. B

Z. Phys.

Phys. Lett. B

Nucl. Phys. A

Phys. Rev. Lett.

Acta Phys. Pol. B

Phys. Rev. Lett.

Phys. Rev. C

Phys. Rev. C

Phys. Lett. B

Phys. Scr. A

Phys. Rev. C

Z. Phys. A

Z. Phys. A

Z. Phys. A

Z. Phys. A

Z. Phys. A

Nucl. Phys. A

Phys. Rev. C

Nucl. Phys. A

Nucl. Phys. A

Nucl. Phys. A

Phys. Lett. B