This article is cited in 5 papers

METHODOLOGICAL NOTES

Extension of the λ curve of ⁴He into the region of the metastable state of liquid helium

V. P. Skripov

Institute of Thermal Physics, Ural Branch, Russian Academy of Sciences, Ekaterinburg

Abstract: A possible extension (λ^') of the λ curve of liquid helium beyond the T, p boiling line, i.e., into the region of a metastable liquid state, is examined. The relation between the slope of the λ curve dp/dT_λ and the sign of the thermal expansion coefficient of liquid helium a_p is discussed. Experimental data for a_p are analyzed using thermodynamic equations to reveal that the derivative dp/dT_λ changes sign in the metastable region. As a result, the shape of the λ^' extension becomes similar to that of the pressure-shifted Bose-condensation line of an ideal ⁴He gas. The position of the λ^' curve is not entirely arbitrary due to the spinodal nature of stretched liquid helium.

PACS: 67.40.-w, 67.40.Kh, 67.90.+z

Received: December 1, 1999

DOI: 10.3367/UFNr.0170.200005f.0559

 English version: Physics–Uspekhi, 2000, 43:5, 515–519

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