Related papers: Negative heat capacity for hot nuclei: confirmatio…
By using freeze-out properties of multifragmenting hot nuclei produced in quasifusion central $^{129}$Xe+$^{nat}$Sn collisions at different beam energies (32, 39, 45 and 50 AMeV) which were estimated by means of a simulation based on…
Simulations based on experimental data obtained from multifragmenting quasi-fused nuclei produced in central $^{129}$Xe + $^{nat}$Sn collisions have been used to deduce event by event freeze-out properties in the thermal excitation energy…
An experimental indication of negative heat capacity in excited nuclear systems is inferred from the event by event study of energy fluctuations in $Au$ quasi-projectile sources formed in $Au+Au$ collisions at 35 A.MeV. The excited source…
Heat capacities of model systems with finite numbers of effective degrees of freedom are evaluated using canonical and microcanonical thermodynamics. Discrepancies between both approaches, which are observed even in the infinite-size limit,…
The microcanonical multifragmentation model from [Al. H. Raduta and Ad. R. Raduta, Phys. Rev. C 55, 1344 (1997); 56, 2059 (1997); 59, 323 (1999)] is refined and improved by taking into account the experimental discrete levels for fragments…
Simulations based on experimental data obtained from multifragmenting quasifused nuclei produced in central 129Xe + natSn collisions have been used to deduce event by event freeze-out properties on the thermal excitation energy range 4-12…
It is shown that negative heat capacity in nanoclusters is an artifact of applying equilibrium thermodynamic formalism on a small system trapped out of equilibrium in a particular structural motif representing only part of the energetically…
Systems with long-range as well with short-range interactions should necessarily have a convex entropy S(E) at proper phase transitions of first order, i.e. when a separation of phases occurs. Here the microcanonical heat capacity c(E)=…
Recent important progress on the knowledge of multifragmentation and phase transition for hot nuclei, thanks to the high detection quality of the INDRA array, is reported. It concerns i) the radial collective energies involved in hot…
Anomalous negative heat capacities have been claimed as indicators of first order phase transitions in finite systems in general, and fornuclear systems in particular. A thermodynamic approach allowing for all Q value terms is used to…
A general discussion is made concerning the ways in which one can get signatures about a possible liquid-gas phase transition in nuclear matter. Microcanonical temperature, heat capacity and second order derivative of the entropy versus…
The heat capacity of iron isotopes is calculated within the interacting shell model using the complete $(pf+0g_{9/2})$-shell. We identify a signature of the pairing transition in the heat capacity that is correlated with the suppression of…
The density profile of a hot nuclear system produced in intermediate energy heavy ion collisions is studied in a microcanonical formulation with a momentum and density dependent finite range interaction. The caloric curve and the density…
Level densities for 93-98Mo have been extracted using the (3He,alpha gamma) and (3He,3He' gamma) reactions. From the level densities thermodynamical quantities such as temperature and heat capacity can be deduced. Data have been analyzed by…
We consider a soluble model of multifragmentation which is similar in spirit to many models which have been used to fit intermediate energy heavy ion collision data. In this model $c_v$ is always positive but for finite nuclei $c_p$ can be…
Heat capacities of Na_N, N = 13, 20, 55, 135, 142, and 147, clusters have been investigated using a many-body Gupta potential and microcanonical molecular dynamics simulations. Negative heat capacities around the cluster melting-like…
An abnormal production of events with almost equal-sized fragments was theoretically proposed as a signature of spinodal instabilities responsible for nuclear multifragmentation in the Fermi energy domain. On the other hand finite size…
Equilibrium statistics of finite Hamiltonian systems is fundamentally described by the microcanonical ensemble (ME). Canonical, or grand-canonical partition functions are deduced from this by Laplace transform. Only in the thermodynamic…
Thermodynamics dictates that the specific heat of a system is strictly non-negative. However, in finite classical systems there are well known theoretical and experimental cases where this rule is violated, in particular finite atomic…
Starting from Antonov's discovery that there is no maximum to the entropy of a gravitating system of point particles at fixed energy in a spherical box if the density contrast between centre and edge exceeds 709, we review progress in the…