X‐ray diffraction from the uniaxial and biaxial nematic phases of bent‐core mesogens

Abstract

X‐ray diffraction patterns for the uniaxial and biaxial nematic phases exhibited by rigid bent‐core mesogens were calculated using a simple model for the molecular form factor and a modified Lorentzian structure factor. The X‐ray diffraction patterns depend strongly on the extent of the alignment of the molecular axes as well as the orientation of molecular planes. The X‐ray diffraction can be unequivocally used to identify the biaxial nematic phase, study the uniaxial–biaxial phase transition, and estimate the order parameters of the nematic phase.

Keywords:

• X‐ray diffraction
• uniaxial–biaxial phase transition
• biaxial nematic phase
• bent‐core mesogen

Acknowledgments

This work was supported, in part, by the National Science Foundation through Grant DMR‐06‐372221. The authors would like to acknowledge Dr. Andrew Primak of Mayo Clinic, Rochester, MN for helpful discussion. Any opinions, findings, and conclusions or recommendations expressed herein are those of the authors and do not necessarily reflect the views of the National Science Foundation.