Heat capacity of the binary liquid system triethylamine–water near the critical solution point

The specific heat Cpx has been measured for the binary system triethylamine–water as a function of temperature near the critical solution temperature at the critical concentration. Simple power law fits of the data resulted in rather large values (around 0.25) for the critical exponent α. For a fixed value of α equal to the Ising value αI=0.125 good fits could only be obtained if more complex expressions were used in fitting the data. For this case the best result was obtained by including a correction-to-scaling term. Combining our result for the amplitude of the specific heat singularity with the correlation length amplitude allowed us to test two-scale-factor universality. Our result strongly indicates that, in contrast to earlier findings, two-scale-factor universality is also valid for binary systems.