Specific heat and bimodality in canonical and grand canonical versions of the thermodynamic model

Abstract

We address two issues in the thermodynamic model for nuclear disassembly. Surprisingly large differences in results for specific heat were seen in predictions from the canonical and grand canonical ensembles when the nuclear system passes from liquid-gas co-existence to the pure gas phase. We are able to pinpoint and understand the reasons for such and other discrepancies when they appear. There is a subtle but important difference in the physics addressed in the two models. In particular if we reformulate the parameters in the canonical model to better approximate the physics addressed in the grand canonical model, calculations for observables converge. Next we turn to the issue of bimodality in the probability distribution of the largest fragment in both canonical and grand canonical ensembles. We demonstrate that this distribution is very closely related to average multiplicities. The relationship of the bimodal distribution to phase transition is discussed.

19 pages, 5 figures

References in corpus (4)

• Bimodality: a possible experimental signature of the liquid-gas phase transition of nuclear matter
• Distribution of the largest fragment in the Lattice Gas Model
• Properties of the largest fragment in multifragmentation: a canonical thermodynamic calculation
• A Model for Phase Transition based on Statistical Disassembly of Nuclei at Intermediate Energies

Cited by in corpus (4)

• Bimodal behavior of the heaviest fragment distribution in projectile fragmentation
• Multiplicity Derivative: A new signature of first order phase transition in intermediate energy heavy ion collision
• Signals of bimodality in the fragmentation of Au quasi-projectiles
• Bimodality and Coulomb effects with a canonical thermodynamic model