Shell Effects in Duflo-Zuker inspired mass formulas: a status report

Deformation and shell effects in nuclear mass formulas

Nuclear Physics A ◽

10.1016/j.nuclphysa.2011.11.005 ◽

2012 ◽

Vol 874 ◽

pp. 81-97 ◽

Cited By ~ 10

Author(s):

César Barbero ◽

Jorge G. Hirsch ◽

Alejandro E. Mariano

Keyword(s):

Nuclear Mass ◽

Shell Effects ◽

Mass Formulas

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SEARCH FOR CORRELATIONS OF MOST PROBABLE NUCLEAR CHARGE ZP OF PRIMARY FISSION FRAGMENTS WITH COMPOSITION AND EXCITATION ENERGY

Canadian Journal of Chemistry ◽

10.1139/v61-078 ◽

1961 ◽

Vol 39 (3) ◽

pp. 646-663 ◽

Cited By ~ 78

Author(s):

Charles D. Coryell ◽

Morton Kaplan ◽

Richard D. Fink

Keyword(s):

Fine Structure ◽

Nuclear Charge ◽

Low Energy ◽

Charge Ratio ◽

Nuclear Chemistry ◽

Fission Process ◽

Shell Effects ◽

Crude Approximation ◽

Charge Displacement ◽

Mass Formulas

The repartition of nuclear charge in fission has a narrower dispersion than almost any other property connected with the fission process. To a crude approximation, the distribution of nuclear charge between light and heavy partners L and H leads to the most probable charges (Zp)L and (ZP)H displaced from the respective charges ZA of β-stability by the same amount for the two fragments (Glendenin rule of equal charge displacement ECD, 1946). The existence of shell offsets in the ZA vs. A function for different neutron- and proton-shell regions must be considered. All available data for thermal fission U235(nth,F) are examined critically. The data show sudden offset-like drifts (fine structure) that may well be associated with shell properties of the products before the "neck" has dissolved. It is shown that these data eliminate naive equal charge displacement ECD, also an older competitive prescription of constant charge ratio CCR for the products, and an empirical Russian prescription (Apalin etal., 1960). The data are also examined in the light of the postulate that fission gives minimum nuclear plus coulombic potential energy (Present 1947, Fong 1955, Swiatecki-Blann 1960), and it is shown that the present mass formulas give too much uncertainty three to four β-decays from stability to give a useful test, but that shell effects in masses must be retained. Data from charged-particle fission with energy deposit up to 40–50 Mev are in reasonable accord with the low-energy data on correcting for composition and neutron boil-off. It is concluded from experiment that ZP is a single-valued function of A, known to about ± 0.15 unit for low-energy fission and ± 0.25 unit for medium-energy fission, and that the fine structure very probably present is an indication of intrinsic nuclear chemistry.

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Progress in the compilation of the FK5

International Astronomical Union Colloquium ◽

10.1017/s0252921100074388 ◽

1978 ◽

Vol 48 ◽

pp. 421-432 ◽

Cited By ~ 7

Author(s):

W. Fricke ◽

W. Gliese

Keyword(s):

Status Report ◽

Magnitude Range

Abstract:Presented is a status report on work on FK5 giving information on the following items: (a) the intended increase of the number of fundamental stars and their magnitude range in FK5, (b) available material for the improvement of the system, (c) methods for the determination of systematic differences, (d) the determination of equator and equinox of FK5, and (e) the elimination of the motion of the FK4 equinox.

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Scanning tunneling microscopy of polymers: A status report

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100153622 ◽

1989 ◽

Vol 47 ◽

pp. 330-331

Author(s):

P.E. Russell ◽

I.H. Musselman

Keyword(s):

High Resolution ◽

Scanning Tunneling Microscopy ◽

Sample Surface ◽

Atomic Scale ◽

Constant Current ◽

Scanning Tunneling ◽

Status Report ◽

Tunneling Microscopy ◽

Research Issues ◽

Wide Range

Scanning tunneling microscopy (STM) has evolved rapidly in the past few years. Major developments have occurred in instrumentation, theory, and in a wide range of applications. In this paper, an overview of the application of STM and related techniques to polymers will be given, followed by a discussion of current research issues and prospects for future developments. The application of STM to polymers can be conveniently divided into the following subject areas: atomic scale imaging of uncoated polymer structures; topographic imaging and metrology of man-made polymer structures; and modification of polymer structures. Since many polymers are poor electrical conductors and hence unsuitable for use as a tunneling electrode, the related atomic force microscopy (AFM) technique which is capable of imaging both conductors and insulators has also been applied to polymers.The STM is well known for its high resolution capabilities in the x, y and z axes (Å in x andy and sub-Å in z). In addition to high resolution capabilities, the STM technique provides true three dimensional information in the constant current mode. In this mode, the STM tip is held at a fixed tunneling current (and a fixed bias voltage) and hence a fixed height above the sample surface while scanning across the sample surface.

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