2born (2born) wrote,

О происхождении гигантского дипольного резонанса

Эх, не было у меня такого текста на 4 курсе!...

The Origin of the Giant Dipole Resonance
Richard B. Firestone
The Giant Dipole Resonance (GDR), which is conventionally described as due to collective motion, is instead shown to be the result of a sudden increase in level density at the 2h{\omega} shell closure. The energy of the GDR closely follows the shell model harmonic oscillator energy model where h{\omega} = 39A^-1/3, for heavy nuclei. A better fit covering the entire mass range is given by h{\omega} = 47:55(0:13)(A^-1/3 - A^-2/3). The GDR is shown to be composed of a lower energy peak, E1, corresponding to the population of levels with oblate deformation and a higher energy peak, E2 corresponding to the population of levels with prolate deformation. The peak energy separation is proportional to the \beta_2 deformation and given by E2-E1 = 11:03(0:22)|\beta_2|. The total photonuclear cross section, sigma = sigma1 + sigma2, populating the GDR is proportional to the level density at the GDR and is given by sigma = 0:483(0:006)A^4/3 where sigma1 = sigma2. The widths of the two GDR peaks are consistent with Nilsson model predictions and found to be Gamma1 = 7:41(0:15)A^-1/6 MeV and Gamma2 = 11:13(0:16)A^-1/6 respectively. The Standard Lorentzian model parameters are fitt to high accuracy as a function of mass and deformation and can be applied reliably to all nuclei. It is shown that the energies of pygmy and spin flip resonances correspond to the E = h{\omega} harmonic oscillator energy and that the giant quadrupole (GQR), giant monopole (GMR), and giant octupole (GOR) resonances coincide with the E = 2-4 h{\omega} harmonic oscillator energies where the level density suddenly increases at the shell gaps.
Comments: 7 pages, 6 figures
Tags: Мегаучебник или Что я читал и похвалил, разгребая arXiv'ы

  • Сегодняшний улов

    Желну не видел, видел только следы его работы, все увеличивающиеся:)) Вот только один пример: DSC_3662_работа_желны_corr.jpg © qedqed.iMGSRC.RU…

  • Сегодяшний лесной пейзажик

    DSC_3158_супер_corr2.jpg © qedqed.iMGSRC.RU

  • Пятничный улов

    был невелик: я сфоткал одного лишь дубоноса, и очень издалека. Но поскольку их у меня ужа два года не было, а я по ним безумно соскучился, опубликую…

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