ISSN:
1089-7690
Quelle:
AIP Digital Archive
Thema:
Physik
,
Chemie und Pharmazie
Notizen:
The tricritical region of quasibinary mixtures of ethane with higher hydrocarbons (n-heptadecane, n-octadecane, n-nonadecane, and their mixtures) has been studied by light scattering from the three phases. The individual susceptibilities, as determined from intensities and correlation lengths, diverge as predicted by the asymptotic mean-field theory, but the Griffiths first sum is neither zero nor constant; instead it increases sharply as the tricritical point is approached. This behavior of the first sum is consistent with a divergence predicted by nonclassical theory or with an approach to the constant limiting value at the tricritical point predicted by an extended classical theory. The Griffiths second sum approaches zero in the way expected from theory (both classical and nonclassical). The ratio of the light-scattering intensities of the outer phases (α and γ) and the corresponding ratios for the correlation lengths do not appear to approach unity as the tricritical point is approached, in disagreement with all present theories, classical or nonclassical.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.454898
