Negative Heat Capacity for a Cluster of 147 Sodium Atoms

Schmidt, M.; Kusche, Robert; Hippler, Thomas; Donges, Jörn; Kronmüller, Werner; Issendorff, Bernd von; Haberland, Hellmut

doi:10.1103/physrevlett.86.1191

Cited by 328 publications

(317 citation statements)

References 14 publications

Supporting

Mentioning

305

Contrasting

Unclassified

Order By: Relevance

“…Self-gravitating or long-range attractive interacting systems exhibit several peculiar features [1][2][3][4], such as gravothermal catastrophe [5,6], negative specific heat [7][8][9], violent relaxation [10], nonequilibrium thermodynamics, and nonextensive statistical mechanics [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. In these systems, the velocity distributions are non-Gaussian [31][32][33], especially in quasiequilibrium states and metastable states.…”

Section: Introductionmentioning

confidence: 99%

Transition of velocity distributions in collapsing self-gravitatingN-body systems

Komatsu

Kiwata

2012

Phys. Rev. E

View full text Add to dashboard Cite

By means of N -body simulations, we study the evolution of gravity-dominated systems from an early relaxation to a collapse, focusing on the velocity distributions and thermodynamic properties. To simulate the dynamical evolution, we consider self-gravitating small N -body systems enclosed in a spherical container with adiabatic or semipermeable walls. It is demonstrated that in the early relaxation process, the velocity distribution is non-Gaussian and q-Gaussian, since the system is in quasiequilibrium states (here q is the Tsallis entropic parameter). Thereafter, the velocity distribution undergoes higher non-Gaussian distributions, especially when the core forms rapidly in the collapse process; i.e., q tends to be larger than that for the quasiequilibrium state, since the velocity distribution further deviates from Gaussian. However, after the core forms sufficiently, the velocity distribution gradually relaxes toward a Gaussian-like distribution. Accordingly, the velocity distribution evolves from a non-Gaussian distribution through a higher non-Gaussian distribution to a Gaussian-like distribution; i.e., the velocity distribution does not monotonically relax toward a Gaussian-like distribution in our collapse simulations. We clearly show such a transition of the velocity distribution, based not only on the Tsallis entropic parameter but also on the ratio of velocity moments. We also find that a negative specific heat occurs in a collapse process with mass and energy loss (such as the escape of stars from globular clusters), even if the velocity distribution is Gaussian-like.

show abstract

Section: Introductionmentioning

confidence: 99%

Transition of velocity distributions in collapsing self-gravitatingN-body systems

Komatsu

Kiwata

2012

Phys. Rev. E

View full text Add to dashboard Cite

show abstract

“…This scaling has now been confirmed in many instances [2,3,4], although a number of exceptions to this general rule have appeared. For instance, as the sensitivity of free nanoparticle calorimetry has improved [5], a so-called 'non-scaling' regime has been observed, where the melting temperature is seen to vary erratically with particle size [6].…”

mentioning

confidence: 99%

Superheating and Solid-Liquid Phase Coexistence in Nanoparticles with Nonmelting Surfaces

Schebarchov

Hendy

2006

Phys. Rev. Lett.

View full text Add to dashboard Cite

We present a phenomenological model of melting in nanoparticles with facets that are only partially wet by their liquid phase. We show that in this model, as the solid nanoparticle seeks to avoid coexistence with the liquid, the microcanonical melting temperature can exceed the bulk melting point, and that the onset of coexistence is a first-order transition. We show that these results are consistent with molecular dynamics simulations of aluminum nanoparticles which remain solid above the bulk melting temperature.

show abstract

“…Once the average becomes independent from the initial condition, the result takes the form of an apparent stationary bimodal distribution. Unlike the stationary distributions of energy reported in the literature [11,32], this time average cannot be interpreted as representative of chemical equilibrium and cannot be used to extract the equilibrium thermodynamic properties of the system [33]. Figure 4 shows the three-dimensional representation of the normalized probability density as a function of for different reduced times.…”

Section: Critical Oscillations Of the Probability Densitymentioning

confidence: 99%

“…3 and 4 of Ref. [32] does not correspond to an equilibrium distribution of energies. It seems instead a time average of a nonequilibrium distribution over a large enough window of time.…”

Section: Critical Oscillations Of the Probability Densitymentioning

confidence: 99%

See 1 more Smart Citation

Thermostatistical description of small systems in nonequilibrium conditions: Energy conversion and harvesting

Santamaría‐Holek

Pérez‐Madrid

2014

Phys. Rev. E

View full text Add to dashboard Cite

Hysteresis cycles are very important features of energy conversion and harvesting devices, such as batteries. The efficiency of these may be strongly affected by the physical size of the system. Here, we show that in systems which are small enough, the existence of physical boundaries which produce nonhomogeneities of the interaction potential gives rise to inflections and barriers in the associated free energy. This in turn brings on irreversible processes which can be triggered under suitable external conditions imposed by a heat bath. As an example, by controlling the temperature, the state of a small system may be impelled to oscillate between two different structural configurations or aggregation states avoiding equilibrium coexistence and therefore dissipating energy. This cyclical behavior associated with a hysteresis cycle may be prototypical of energy conversion, storage, or generating nanodevices, as exemplified by Li-ion insertion batteries.

show abstract

Negative Heat Capacity for a Cluster of 147 Sodium Atoms

Cited by 328 publications

References 14 publications

Transition of velocity distributions in collapsing self-gravitatingN-body systems

Transition of velocity distributions in collapsing self-gravitatingN-body systems

Superheating and Solid-Liquid Phase Coexistence in Nanoparticles with Nonmelting Surfaces

Thermostatistical description of small systems in nonequilibrium conditions: Energy conversion and harvesting

Contact Info

Product

Resources

About