Combination of separate smectic-C-alpha phases in binary mixtures*

Applying resonant x-ray diffraction, we showed that the two previously considered separate smectic-$C^*_{\alpha}$ phases were combined into a single phase in a series of binary mixtures. The pitch evolved continuously and smoothly, contradicting a previously successful theoretical model. New phase sequences found in our studies can be explained by a newer model. The comparison indicates long-range interactions exist in the smectics.