Two liquid states of matter: A dynamic line on a phase diagram

Бражкин, В. В.; Fomin, Yu. D.; Lyapin, A. G.; Ryzhov, V. N.; Trachenko, Kostya

doi:10.1103/physreve.85.031203

Cited by 245 publications

(333 citation statements)

References 41 publications

Supporting

Mentioning

314

Contrasting

Unclassified

Order By: Relevance

“…(b): longitudinal (filled black bullets) and transverse (filled red bullets) excitations in liquid Na. Open diamonds correspond to longitudinal (black) and transverse (red) excitations in polycrystalline Na, and dashed-dotted lines to longitudinal (black) and transverse (red) branches along [111] direction in Na single crystal [70]. (c): longitudinal (black bullets) and transverse (red bullets) excitation in liquid Ga.…”

Section: Experimental Evidence For High-frequency Collective Modes Inmentioning

confidence: 99%

“…We have recently proposed that this picture should be modified, and that a new line, the Frenkel line (FL), exists above the critical point and separates two states with distinct properties (see Figure 10) [111][112][113][114]. The main idea of the FL lies in considering how particle dynamics changes in response to pressure and temperature.…”

Section: Frenkel Linementioning

confidence: 99%

See 1 more Smart Citation

Collective modes and thermodynamics of the liquid state

2015

View full text Add to dashboard Cite

Strongly interacting, dynamically disordered and with no small parameter, liquids took a theoretical status between gases and solids, with the historical tradition of hydrodynamic description as the starting point. We review different approaches to liquids as well as recent experimental and theoretical work, and propose that liquids do not need classifying in terms of their proximity to gases and solids or any categorizing for that matter. Instead, they are a unique system in their own class with a notably mixed dynamical state in contrast to pure dynamical states of solids and gases. We start with explaining how the first-principles approach to liquids is an intractable, exponentially complex problem of coupled non-linear oscillators with bifurcations. This is followed by a reduction of the problem based on liquid relaxation time τ representing non-perturbative treatment of strong interactions. On the basis of τ , solid-like high-frequency modes are predicted and we review related recent experiments. We demonstrate how the propagation of these modes can be derived by generalizing either hydrodynamic or elasticity equations. We comment on the historical trend to approach liquids using hydrodynamics and compare it to an alternative solid-like approach. We subsequently discuss how collective modes evolve with temperature and how this evolution affects liquid energy and heat capacity as well as other properties such as fast sound. Here, our emphasis is on understanding experimental data in real, rather than model, liquids. Highlighting the dominant role of solid-like high-frequency modes for liquid energy and heat capacity, we review a wide range of liquids: subcritical low-viscous liquids, supercritical state with two different dynamical and thermodynamic regimes separated by the Frenkel line, highly-viscous liquids in the glass transformation range and liquid-glass transition. We subsequently discuss the fairly recent area of liquid-liquid phase transitions, the area where the solid-like properties of liquids have become further apparent. We then discuss gas-like and solid-like approaches to quantum liquids and theoretical issues that are similar to the classical case. Finally, we summarize the emergent view of liquids as a unique system in a mixed dynamical state, and list several areas where interesting insights may appear and continue the extraordinary liquid story.

show abstract

Section: Experimental Evidence For High-frequency Collective Modes Inmentioning

confidence: 99%

Section: Frenkel Linementioning

confidence: 99%

Collective modes and thermodynamics of the liquid state

2015

View full text Add to dashboard Cite

show abstract

“…The Frenkel line has recently been proposed, which separates two dynamically distinct states: the gas-like regime where particle only have diffusive motion and the liquidlike regime where particle combine both solid-like quasiharmonic vibrational motion and gas-like diffusive motion [13][14][15]. This transition take place when liquid relaxation time τ approaches Debye vibration period, τ D .…”

mentioning

confidence: 99%

Frenkel line and solubility maximum in supercritical fluids

et al. 2015

Self Cite

View full text Add to dashboard Cite

A new dynamic line, the Frenkel line, has recently been proposed to separate the supercritical state into rigid-liquid and non-rigid gas-like fluid. The location of Frenkel line on the phase diagram is unknown for real fluids. Here, we map the Frenkel line for three important systems: CO2, H2O and CH4. This provides an important demarcation on the phase diagram of these systems, the demarcation that separates two distinct physical states with liquid-like and gas-like properties. We find that the Frenkel line can have similar trend as the melting line above the critical pressure. Moreover, we discuss the relationship between unexplained solubility maxima and Frenkel line, and propose that the Frenkel line corresponds to the optimal conditions for solubility.Recently, there has been a dramatical increase of using supercritical fluids in extraction and purification applications, including in food, nuclear waste, petrochemical and pharmaceutical industries [1][2][3][4]. Supercritical fluids attract significant attention due to their extremely good dissolving power and "tunable" properties. The solubility of supercritical fluids depend on density and diffusivity. Supercritical fluids combine the best of both worlds: high density of liquids and large diffusion constants of gases. Moreover, both of those properties can be tuned over a wide range pressure and temperature above the critical point, optimizing their dissolving ability.Carbon dioxide, water and methane are three most commonly used supercritical fluids. In particular, H 2 O and CO 2 , are both abundant, non flammable and non toxic. They are also "non-polar" and "polar" solvent, respectively, so they can dissolve "polar" and "non-polar" solutes, respectively. The critical temperature (T c ) of CO 2 is at 304 K, which is near the room temperature, and the critical pressure (P c ) is 74 bar, which is also accessible. Additionally, CO 2 can be used with co-solvents to modify it into "polar" solvent.The solubility of variety of solutes have been measured in supercritical CO 2 near the T c as a function of pressure [1]. Interestingly, the experiment show intriguing solubility maxima above critical temperature: solubility first substantially increase with pressure, followed by its decrease at higher pressure [5][6][7][8][9][10][11][12]. This effect is not currently understood theoretically. Understanding it would lead to more efficiently use of supercritical fluids. More generally, it is often acknowledged that wider deployment of supercritical fluids and optimizing their use would benefit from a theoretical guidance [1,2].Until recently, supercritical state was believed to be physically homogeneous, which means that moving along any path on a pressure and temperature above the critical point does not involve marked or distinct changes. The Frenkel line has recently been proposed, which separates two dynamically distinct states: the gas-like regime where particle only have diffusive motion and the liquidlike regime where particle combine both solid-like quasiharmon...

show abstract

“…In the simplest case the interaction energy is approximated by pair interactions only. Among the most studied in the literature is Lennard-Jones (LJ) system which has the potential U (r) = ε This system demonstrates a generic view of phase diagram of a substance containing gas, liquid and crystal phases and well describes the behavior of noble gases and some molecular substances.In our recent works it was shown that supercritical region of the phase diagram can be divided into two parts: rigid liquid and dense gas [1][2][3]. These regions differ by the microscopic dynamics of particles and are separated by a crossover line called Frenkel line.…”

mentioning

confidence: 99%

“…Several criteria can be used to locate the line of dynamical crossover [1][2][3]. Among the most convenient ones are the velocity autocorrelation function (vacf) criterion and the isochoric heat capacity one [3].…”

mentioning

confidence: 99%

Dynamical crossover in supercritical core-softened fluids

Gaiduk

Fomin

Ryzhov

et al. 2016

Fluid Phase Equilibria

Self Cite

View full text Add to dashboard Cite

It is well known that some liquids can demonstrate anomalous behavior. Interestingly, this behavior can be qualitatively reproduced with simple core-softened isotropic pair-potential systems. Although anomalous properties of liquids usually take place at low and moderate temperatures it was recently recognized that many important phenomena can appear in supercritical fluids. However, no studies of supercritical behavior of core-softened fluids is reported. This paper reports a study of dynamical crossover in supercritical core-softened systems. The crossover line is calculated from three different criteria and good agreement between them is observed. It is found that the behavior of the dynamical crossover line of core-softened systems is quite complex due to its quasi-binary nature. The most fundamental approach to the behavior of matter relies on the interactions between the particles of the substance. One can use an approach based on quantum mechanical treatment of interactions which is the most accurate one. However, such ab-initio methods require a lot of computational resources and cannot be applied to the systems larger then several hundreds of atoms. A great advantage was made by application of so called effective potentials. These potentials are constructed in such a way that they allow to obtain some principal properties of interest with much smaller efforts. In the simplest case the interaction energy is approximated by pair interactions only. Among the most studied in the literature is Lennard-Jones (LJ) system which has the potential U (r) = ε This system demonstrates a generic view of phase diagram of a substance containing gas, liquid and crystal phases and well describes the behavior of noble gases and some molecular substances.In our recent works it was shown that supercritical region of the phase diagram can be divided into two parts: rigid liquid and dense gas [1][2][3]. These regions differ by the microscopic dynamics of particles and are separated by a crossover line called Frenkel line. Later on the phenomenon of dynamical crossover was studied for a number of other fluids [4][5][6][7][8].Another topic attracting wide attention of researchers is related to anomalous behavior of liquids (see, for example, [9] for the list of anomalies of water). It was found that models with isotropic pair core-softened potentials can demonstrate anomalous behavior [10][11][12][13][14][15][16][17]. Diffusion, density and structural anomalies are widely discussed in the literature [18]. Such systems can also demonstrate numerous structural phase transitions in solid region. This kind of behavior cannot be obtained in systems like LJ. These observations allow to suppose that the behavior of the Frenkel line can also be more complex in the systems with core-softened potentials.A particular form of core-softened system studied in our previous works is characterized by the following interaction potential:where d and ε set the length and energy scales and λ i and σ i are varied. A large set of parameters was cons...

show abstract

Two liquid states of matter: A dynamic line on a phase diagram

Cited by 245 publications

References 41 publications

Collective modes and thermodynamics of the liquid state

Collective modes and thermodynamics of the liquid state

Frenkel line and solubility maximum in supercritical fluids

Dynamical crossover in supercritical core-softened fluids

Contact Info

Product

Resources

About