We present existing theory on two-dimensional transitions (appropriate to thin parallel-plate geometries) in such a way that one can identify easily conditions for the onset of shallow cells. By doing so we can give conditions under which succinonitrile-acetone mixtures should undergo supercritical bifurcation in experimentally accessible ranges. These results suggest a means for the quantitative test of the Mullins and Sekerka model and its weakly nonlinear extensions.

• Received 10 April 1989

DOI:https://doi.org/10.1103/PhysRevLett.63.573