Coexistence Curve ofHe4Near the Critical Point

Abstract

The coexistence curve of ${\mathrm{He}}^4$ has been measured over the range $0.1 \mathrm{mdeg}<T_c-T<\mathrm{}250\mathrm{} \mathrm{mdeg}$. The data for $T_c-T<\mathrm{}100\mathrm{}$ mdeg fit an expression of the form $|\rho -{\rho }_c|\propto {(P_c-P)}^{{\beta }_P}$, where $\rho$ is the density of either the liquid or the vapor, and $P$ is the pressure; ${\rho }_c=0.0701\mathrm{}\pm 0.0006$ g/${\mathrm{cm}}^3$, $P_c=1705.0\mathrm{}\pm 0.8$ Torr [$T_c=5.1890\mathrm{}\pm 0.0006°$K], and ${\beta }_P=0.355\mathrm{}\pm 0.004$.