Summary: VOLUME 76, NUMBER 2 P H Y S I C A L R E V I E W L E T T E R S 8 JANUARY 1996
Origin of Traveling Rolls in Electroconvection of Nematic Liquid Crystals
and David S. Cannell1
Department of Physics and Center for Nonlinear Science, University of California at Santa Barbara,
Santa Barbara, California 93106
Physikalisches Institut der Universitšt Bayreuth, D-95440 Bayreuth, Germany
(Received 3 May 1995)
Electroconvection in nematic liquid crystals exhibits a Hopf bifurcation to traveling rolls for a wide
parameter range. The model normally used to describe electroconvection fails to predict this. A recent
theoretical extension, the weak-electrolyte model, incorporates the dissociation-recombination reaction
of the ionic dopant in the sample and does predict a Hopf bifurcation for a range of parameter values.
We present a quantitative experimental test of this theory using the nematic liquid crystal I52. Measured
Hopf frequencies at the onset of convection agree well with the theory.
PACS numbers: 83.70.Jr, 47.20.Ky, 47.65.+a