Examinando por Autor "Pomar, C."

Mostrando 1 - 6 de 6
  • Miniatura
    ÍtemAcceso Abierto
    A graphical procedure to evaluate the many-body shell-model equations
    (North Holland Publishin Co., 1982) Liotta, R. I.; Pomar, C.
    The many-body shell-model equations are solved within the framework of a multistep shell-model method (MSM). It is found that there are many different ways to proceed through such a method. A graphical procedure to evaluate all the corresponding MSM equations is presented. Within this procedure one can easily visualize all those possibilities and quickly choose the most convenient one. This graphical procedure is applied to calculate ground-state energies and wave functions in many-nucleon systems and good agreement with experimental data is obtained. Las ecuaciones del modelo de caparazón de muchos cuerpos se resuelven en el marco de un método de modelo de caparazón (MSM) de varios pasos. Se encuentra que hay muchas maneras diferentes de proceder a través de tal método. Se presenta un procedimiento gráfico para evaluar todas las ecuaciones MSM correspondientes. Dentro de este procedimiento uno puede visualizar fácilmente todas esas posibilidades y elegir rápidamente la más conveniente. Este procedimiento gráfico se aplica para calcular las energías del estado fundamental y las funciones de onda en sistemas de muchos nucleones y se obtiene una buena concordancia con los datos experimentales.
  • Miniatura
    ÍtemAcceso Abierto
    A Reformulation of the Mode-Goupling Method
    (1980) Liotta, R. J.; Pomar, C.; Silvestre-Brac, B. A.
    In the last few years several attempts have been made to include the two-particle and particle-hole correlated states as basis states in the description of nuclear spectra In particular, it bas been shown tbat the weak-coupling model (WCM) reproduces well the exact shell-model calculated states in 2ospb also been proved that the mode-coupling method (MCM) gives the exact shell-model energies in a number of situations.
  • Miniatura
    ÍtemAcceso Abierto
    Graphical multistep shell-model calculation of the even tin and lead ground states
    (The American Physical Society, 1982) Pomar, C.; Liotta, R. J.
    The ground-state energies and wave functions of tin and lead even isotopes are calculated within a multistep shell-model method and good agreement with experimental data is obtained. To carry out this calculation a general graphical procedure is introduced.
  • Miniatura
    ÍtemAcceso Abierto
    Microscopic description of yrast states in spherical nuclei
    (1982) Liotta, R. I.; Pomar, C.
    The dynamical equations that control a many-body nucleus are derived in terms of correlated subsystems. The energies of states which can be described within one vector of the correlated basis are calculated. It is found that for yrast states those energies agree weil with experimental data. Las ecuaciones dinámicas que controlan un núcleo de muchos cuerpos se derivan en términos de subsistemas correlacionados. Se calculan las energías de los estados que pueden describirse dentro de un vector de la base correlacionada. Se encuentra que para los estados yrast esas energías concuerdan bien con los datos experimentales.
  • Miniatura
    ÍtemAcceso Abierto
    Multi-step shell-model method. The nuclei 204pb and 202pb.
    (North Holland Publishing Co., 1980) Pomar, C.; Liotta, R. J.
    In this paper we present an extension of the method given in ref. [7] to analyse four- and six-particle systems outside closed-shell cores. The basic idea of the method presented here is to use the two-particle spectrum components as building blocks to describe the four-particle system (the so-called two-phonon states [3, 5, 6]). Once the four-particle spectrum is obtained, we use this spectrum and that of the two-particle system as building blocks to describe the six-particle system. Actually, other partitions are also possible. For instance, one can solve the six-particle system in terms of the five- and the one-particle spectra. We chose the partition mentioned above because we have in mind to analyze the (p, t) experimental data of ref. [8] for which our choice seems natural.
  • Miniatura
    ÍtemAcceso Abierto
    Multi-step shell-model treatment of six-particle systems
    (North Holland Publishin Co., 1981) Liotta, R. J.; Pomar, C.
    A method is presented of solving the six-particle systems in several steps. In the first step, the two-particle spectrum is calculated within the standard shell model. In the second step, the four-particle system is solved within a (correlated) basis consisting of the vector-coupled two-particle states previously evaluated. Finally, in the third step the six-particle system is calculated using a basis formed by vector coupling the two- and four-particle spectra evaluated in the first two steps. The method is applied to analyse the spectra and (p, t) reactions leading to 204Pb and 202Pb and good agreement with experimental data is obtained. A liaison between this calculation and the pairing model is found and the importance of the Pauli principle upon the pairing vibrational states is attested.