skip to main content
Idioma:
Primo Search
Clear Search Box
Search in: Busca Geral
Busca Avançada
Busca por Índices

Comparison of saddle point and exact combinatorial level densities

da Fonseca e Oliveira, N C ; Dutra, M ; Carlson, B V

Journal of physics. Conference series, 2019-07, Vol.1291 (1), p.12042 [Periódico revisado por pares]

Bristol: IOP Publishing

Texto completo disponível

Citações Citado por
  • Título:
    Comparison of saddle point and exact combinatorial level densities
  • Autor: da Fonseca e Oliveira, N C ; Dutra, M ; Carlson, B V
  • Assuntos: Approximation ; Combinatorial analysis ; Laplace transforms ; Mathematical analysis ; Nuclear reactions ; Particle density (concentration) ; Partitions (mathematics) ; Saddle points
  • É parte de: Journal of physics. Conference series, 2019-07, Vol.1291 (1), p.12042
  • Descrição: Accurate level densities are an important ingredient in the calculation of compound nucleus emission cross sections. They are often approximated numerically using the saddle point approximation to the canonical level density obtained from the grand canonical partition function using the inverse Laplace transform. Here, we use a modified version of the saddle-point approximation proposed by Rossignoli to obtain canonical level densities and average properties of a system. However, the level density needed in nuclear reaction calculations is actually the energy-conserving microcanonical one. For simple systems, the latter can be calculated combinatorially. Here we calculate microcanonical level densities using an evenly-spaced single particle density for one type of nucleon and compare these to saddle-point canonical level densities obtained from the same single-particle density. The simplest continuous approximation to the microcanonical level density describes it well near its peak but poorly at low excitation energies. The canonical level density obtained from the partition function fares somewhat better but is still not completely successful. It tends to exceed the exact result by a few percent. We discuss the differences between the canonical and microcanonical level densities and suggest how these might be reduced.
  • Editor: Bristol: IOP Publishing
  • Idioma: Inglês
Voltar para lista de resultados

  • Realização: ABCD-USP USP   Logos de Redes Sociais: Freepik

Buscando em bases de dados remotas. Favor aguardar.