Corrections to scaling in the susceptibility of xenon

Abstract

We report the first measurements of the susceptibility of a pure fluid near its critical point made with sufficient accuracy to directly reveal the existence of corrections to scaling. The measurements were made on the critical isochore for $T>\mathrm{}{T}_c$, in the range $9.6\times {10}^{-5\mathrm{}}\le t\le {10}^{-1\mathrm{}}$, and are described to within 0.11% rms deviation by the expression $\chi ={\Gamma }^{+}{t}^{-\gamma }(1+a_1{t}^{\Delta }+a_2{t}^{2\Delta }+a_3{t}^{3\Delta })$, with $\Delta$ fixed at 0.496, $\gamma =1.246\mathrm{}\pm 0.010$, and $a_1=1.6\mathrm{}\pm 0.3$. The measurements are consistent with either the high-temperature series result $\gamma =1.250\mathrm{}$, or the renormalization-group result $\gamma =1.241\mathrm{}$. With $\gamma$ fixed at 1.241, the value assumed by $a_1$ is 1.3±0.2. The effects of revised scaling are considered using a parametric model, and are found not to affect the results for ${\Gamma }^{+}$, $a_1$, or $\gamma$.