Molar Volume, Coefficient of Thermal Expansion, and Related Properties of LiquidHe4under Pressure

From measurements of the dielectric constant, we have determined the molar volume of liquid ${\mathrm{He}}^4$ along various isobars in the region 1.25 to 4.2°K and 0.5 to 28 atm. Tables of molar volume, thermal expansion co-efficient ${\alpha }_P$, entropy of compression, and isobaric change in the isothermal compressibility are presented for this region. Values of $T_{\lambda }$, $P_{\lambda }$, and $V_{\lambda }$ are presented. Particular emphasis was put on the form of the expansion coefficient near the $\lambda$ transition. We have found that the ${\alpha }_P$ singularity is logarithmic over the range of 2×${10}^{-5\mathrm{}}$ to ${10}^{-2\mathrm{}}$°K displacement from the transition, and from the data that lead to this conclusion, we have been able to calculate various other properties of the fluid near the transition. These results are compared with those of other experiments wherever possible.