Advertisement

Pramana

, Volume 40, Issue 4, pp 311–320 | Cite as

Collective dipole oscillations in atomic nuclei and small metal particles

  • R S Bhalerao
  • Mustansir Barma
Article

Abstract

The systematics of photon absorption cross sections in nuclei and small metal particles are examined as a function of the number of constituent fermionsA. It is pointed out that the shell-structure-linked oscillations in the full width at half maximum (FWHM) of the photoneutron cross section in nuclei, earlier recognized forA>63, in fact persist down to the lightest nuclei. Averaging over the oscillations or focusing on the lower envelope of the oscillating curve (magic nuclei), the FWHM is seen to generally decrease with increasingA, consistent withA −1/3, a dependence which was earlier known to hold in metal particle systems. If the FWHMs are scaled by the respective Fermi energies and the inverse radii by the Fermi wave vectors, the two data sets become comparable in magnitude. A schematic theoretical description of the systematics is presented.

Keywords

Giant dipole resonance Mie resonance small metal particles metal clusters shell effects size dependence 

PACS Nos

24.30 25.20 36.40 78.40 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. [1]
    S Sugano, inMicroclusters edited by S Sugano, Y Nishina and S Ohnishi (Springer Berlin, 1987)Google Scholar
  2. [2]
    W A de Heer, W D Knight, M Y Chou and M L Cohen,Solid state physics 40, 93 (1987)CrossRefGoogle Scholar
  3. [3]
    B L Berman and S C Fultz,Rev. Mod. Phys. 47, 713 (1975)CrossRefADSGoogle Scholar
  4. [4]
    A van der Woude,Prog. Part. Nucl. Phys. 18, 217 (1987)CrossRefADSGoogle Scholar
  5. [5]
    M Born and E Wolf,Principles of optics (Pergamon, Oxford, 1970) ch. 13Google Scholar
  6. [6]
    S P Apell, J Giraldo and S Lundqvist,Phase Transitions 24–26, 577 (1990)CrossRefGoogle Scholar
  7. [7]
    V V Kresin,Phys. Rep. 220, 1 (1992)CrossRefADSGoogle Scholar
  8. [8]
    M Barma and R S Bhalerao, inPhysics and chemistry of finite systems: from clusters to crystals edited by P Jena, S N Khanna and B K Rao (Kluwer, Dordrecht, 1992) NATO ASI Sr.Vol II, p. 881Google Scholar
  9. [9]
    S S Dietrich and B L Berman,At. Data Nucl. Data Tables 38, 199 (1988)CrossRefADSGoogle Scholar
  10. [10]
    R Bergère, inPhotonuclear reactions edited by S Costa and C Schaerf, Lecture Notes in Physics (Springer, Berlin, 1977)61, 114Google Scholar
  11. [11]
    K A Snover,Ann. Rev. Nucl. Part. Sci. 36, 545 (1986)CrossRefADSGoogle Scholar
  12. [12]
    Although28Si is not a magic nucleus, it displays behaviour similar to a magic nucleus in at least one other context: the plot of nuclear electric quadrupole moment vsZ orN passes through a zero near28Si, indicating a prolate to oblate transition. Similar transitions also occur at the magic numbers [13].Google Scholar
  13. [13]
    M A Preston and R K Bhaduri,Structure of the nucleus (Addison-Wesley, Reading, 1975 figs. 3.2 and 10.12 pages 73 and 470Google Scholar
  14. [14]
    U Kreibig and L Genzel,Surf. Sci. 156, 678 (1985)CrossRefADSGoogle Scholar
  15. [15]
    K Selby, M Vollmer, J Masui, W A de Heer and W D Knight,Phys. Rev. B40, 5417 (1989)ADSGoogle Scholar
  16. [16]
    K Selby, V Kresin, J Masui, M Vollmer, A Scheidemann and W D Knight,Z. Phys. D19, 43 (1991)ADSGoogle Scholar
  17. [17]
    J Tiggesbäumker, L Köller, H O Lutz and K H Meiwes-Broer,Chem. Phys. Lett. 190, 42Google Scholar
  18. [18]
    W D Myers, W J Swiatecki, T Kodama, L J El-Jaick and E R Hilf,Phys. Rev. C15, 2032 (1977)ADSGoogle Scholar
  19. [19]
    K P Charlé, W Schulze and B WinterZ. Phys. D12, 471 (1989)ADSGoogle Scholar
  20. [20]
    N W Ashcroft and N D Mermin,Solid state physics (Holt, Rinehart and Winston, New York, 1976) ch. 1Google Scholar
  21. [21]
    M Goldhaber and E Teller,Phys. Rev. 74, 1046 (1948)CrossRefADSGoogle Scholar
  22. [22]
    H Steinwedel and J H D Jensen,Z. Naturforschung 5a, 413 (1950)ADSGoogle Scholar
  23. [23]
    U Kreibig,J. Phys. F4, 999 (1974)CrossRefADSGoogle Scholar
  24. [24]
    A Kawabata and R Kubo,J. Phys. Soc. Jpn. 21, 1765 (1966)CrossRefADSGoogle Scholar
  25. [25]
    M Barma and V Subrahmanyam,J. Phys. Cond. Matter 1, 7681 (1989)CrossRefADSGoogle Scholar
  26. [26]
    C Yannouleas and R Broglia,Ann. Phys. (NY) 217, 105 (1992)CrossRefADSGoogle Scholar
  27. [27]
    D M Brink,Nucl. Phys. 4, 215 (1957)CrossRefGoogle Scholar
  28. [28]
    J Blocki, Y Boneh, J R Nix, J Randrup, M Robel, A J Sierk and W J Swiatecki,Ann. Phys. (NY) 113, 330 (1978)CrossRefADSGoogle Scholar
  29. [29]
    C Yannouleas,Nucl. Phys. A439, 336 (1985)ADSGoogle Scholar
  30. [30]
    J Wambach,Rep. Prog. Phys. 51, 989 (1988)CrossRefADSGoogle Scholar
  31. [31]
    For real nuclei, the full two-body contribution Γ may differ significantly from Γ.Google Scholar
  32. [32]
    K Okamoto,Phys. Rev. 110, 143 (1958)CrossRefADSGoogle Scholar
  33. [33]
    This is in contrast to the statements made in various reviews [34–37] that the width, likeω 0, varies smoothly withA.Google Scholar
  34. [34]
    J Speth and A van der Woude,Rep. Prog. Phys. 44, 719 (1981)CrossRefADSGoogle Scholar
  35. [35]
    K Goeke and J Speth,Ann. Rev. Nucl. Part. Sci. 32, 65 (1982)CrossRefADSGoogle Scholar
  36. [36]
    M N Harakesh, contribution toXVII Summer School on nuclear structure by means of nuclear reactions, Mikolajki, Polland 1985 (unpublished)Google Scholar
  37. [37]
    A van der Woude, inelectric and magnetic giant resonances in nuclei edited by J Speth (World Scientific, Singapore, 1991 100Google Scholar

Copyright information

© Indian Academy of Sciences 1993

Authors and Affiliations

  1. 1.Theoretical Physics GroupTata Institute of Fundamental ResearchBombayIndia

Personalised recommendations