Iodine-129 Mössbauer spectroscopy: Probing the molecular orientation in liquid crystals

Abstract
A series of I129 Mössbauer measurements have been completed on 4nhexoxybenzylidene4iodoaniline129 dissolved in the liquid crystal 4nhexoxybenzylidine4npropylaniline. Ordered solute "monocrystals" were produced by orienting the samples in an external magnetic field. The sample exhibited three liquid-crystalline phases: nematic, smectic A, and smectic H. Analysis of the I129 Mössbauer spectra gave a value of 50 ± 4° for the smectic-H tilt angle.