Xu Jiadi, Dong Ronald Y
Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB, Canada R3T 2N2.
J Phys Chem B. 2006 Jan 26;110(3):1221-8. doi: 10.1021/jp055868w.
A deuterium two-dimensional exchange NMR technique is used to study the chiral smectic C (SmC*) and chiral subphases (SmC*(Fi1), SmC*(Fi2)) of a smectogen (s)-1-methylheptyl 4'-(4-n-decyloxy-benzoyloxy)biphenyl-4-carboxylate (10B1M7). The aim is to demonstrate how this technique can be combined with sample rotation in the magnetic field to obtain the fast translational self-diffusion constant along the helical pitch in the SmC* phase and to shed light on the structure of helicoidal superlattice in the three-layer SmC*(Fi1) and four-layer SmC*(Fi2) phases. The cross-peak intensities in the 2D exchange spectrum are sensitive to the disposition of molecules in the three- and four-layer base unit. The results support the "asymmetric Clock model" as an appropriate description of the ferrielectric phases in this compound.
利用氘二维交换核磁共振技术研究了近晶原（s）-1-甲基庚基4'-（4-正癸氧基-苯甲酰氧基）联苯-4-羧酸酯（10B1M7）的手性近晶C相（SmC*）和手性亚相（SmC*(Fi1)、SmC*(Fi2)）。目的是展示如何将该技术与磁场中的样品旋转相结合，以获得SmC相沿螺旋节距的快速平移自扩散常数，并阐明三层SmC(Fi1)和四层SmC*(Fi2)相中的螺旋超晶格结构。二维交换谱中的交叉峰强度对三层和四层基本单元中分子的排列敏感。结果支持“不对称时钟模型”作为该化合物中铁电相的合适描述。
