On the nature of the tensile instability in metastable liquids and its relationship to density anomalies

Abstract

Comparison of the pseudospinodal to the transition from metastability to instability in a binaryliquid mixture J. Chem. Phys. 94, 8630 (1991); 10.1063/1.460050Erratum: On the nature of the tensile instability in metastable liquids and its relationship to density anomalies [J.Tensile instability is a hitherto unexplained phenomenon whereby a metastable liquid loses tensile strength as the temperature is reduced in the vicinity of its triple point. The thermodynamically consistent behavior which must be exhibited by any liquid in the vicinity of a tensile instability displays a variety of unusual phenomena: nonanalytic density maxima, spinodal retracing, and density anomalies (negative thermal expansion coefficient) in the vicinity of the spinodal curve. Loss of tensile strength implies (and is inseparable from) density anomalies in the vicinity of the spinodal curve. This important conclusion is derived here from first principles.

Cooperative molecular motions in water: The liquid-liquid critical point hypothesis

“…For example, the collective excitations that occur at low frequency and large wave vector [71] have been the object of much recent work [72,73]. Also, the full implications of a re-entrant spinodal possibility [74][75][76][77] may not have been fully incorporated into our understanding of water. The minimum exhibited by the adiabatic compressibility in atmospheric pressure experiments [78] is of potential relevance since a maximum in any quantity that would be singular at a spinodal may be relevant to placing the critical point at a larger pressure than atmospheric.…”

Is there a second critical point in liquid water?

“…Further important progress in this field has been made by Speedy [9] for the case of water and generalized to arbitrary fluids by Debenedetti and his colleagues [16][17][18][19][20]. They have observed that liquids having a line of density maxima which has a negative slope in the P-T plane of their phase diagram should possess a region where the line of density maxima and the liquid spinodal line meet.…”

“…The importance of this task argues for a strong effort in implementing MD programs for waterlike potentials on new powerful parallel computers. Analytical work on simple potentials showing a density maximum should also be pursued; already such approaches have revealed a rich set of possible behaviors [16][17][18][19][20][34][35][36][37] ]. If our data are confirmed by these extensive checks, then it will become important to perform experiments as close as possible to the new critical point, which according to the P and T shift used above, should be located in real water at T = 185 K and P = 120 Pa. At the same time, we hope that measurements in the stretched region can be extended to search for the change in slope of the line of density maxima [38 ].…”

Liquid–liquid critical point in supercooled silicon

“…We construct the phase diagram of supercooled silicon, which reveals the interconnection between thermodynamic anomalies and the phase behaviour of the system as suggested in previous works [3][4][5][6][7][8][9][10] . We also observe a strong relationship between local geometry (quantified by the coordination number) and diffusivity, both of which change dramatically with decreasing temperature and pressure.The possibility of a phase transition between two forms of the liquid phase in some pure substances has attracted considerable interest and research activity in recent years [1][2][3][4][5][6][7][8][9][10] . Among the substances investigated are water 6,8,9 , silica 10 , silicon 1,11-17 , germanium, carbon and hydrogen-these substances together form a very significant component of our natural world, living organisms and technology.…”