Absolute Value of the Surface Tension of Liquid 4He

In 1985 Iino et al. J. Low Temp. Phys. 61, 155 (1985)] measured the surface tension of liquid ⁴ He by the surface-wave resonance method, and reported that the surface tension at 0K is 354 N/m. Recently, Roche et al. J. Low Temp. Phys. 106, 565 (1997)] obtained the absolute value at 0K to be 375 N/m from the dispersion relation of a capillary wave at a micron wavelength. There is a 6% discrepancy between those two values. To determine the meniscus effects for the surface waves and the absolute value of the surface tension, we measured the resonance frequencies of the surface wave in two parallelepiped cavities with different widths. By comparing the same wave number of the two cavities, it was found that the resonance frequencies are shifted to be slightly smaller by the meniscus effects. The absolute value of the surface tension, which was obtained by eliminating these effects by using the resonance frequencies of the two cavities, was in agreement with that of Iino et al.