Domenici Valentina, Geppi Marco, Veracini Carlo Alberto, Zakharov Alexandre V
Dipartimento di Chimica e Chimica Industriale, Università degli studi di Pisa, via Risorgimento 35, 56126, Italy.
J Phys Chem B. 2005 Oct 6;109(39):18369-77. doi: 10.1021/jp053028b.
In this work, the rotational-diffusion coefficients D(parallel) and D(perpendicular) for the ferroelectric smectogen (+)-(S)-4-[4'-(1-methylheptyloxy)] biphenyl 4-(10-undecenyloxy)benzoate have been studied by means of 2H NMR spectroscopy in the smectic C phase, using a new theoretical approach (Domenici,V.; Geppi, M.; Veracini, C. A. Chem. Phys. Lett. 2003, 382, 518). The analysis of spin-lattice relaxation times has been performed in terms of the diffusional constant and the activation energy of the internal and overall molecular-reorientational motions, and the results are compared to the smectic A (SmA) phase. Moreover, from the 2H NMR data in the SmA phase, the dielectric permittivity and the dielectric relaxation time functions are investigated using a theoretical approach. The longitudinal and transverse components of the real Rchigammaomega and imaginary chigammaomega (gamma = parallel, perpendicular) parts of the complex susceptibility tensor and the nematic-like rotational-viscosity coefficients, lambda2 and lambda5, are calculated.
在本工作中，利用一种新的理论方法（多梅尼西，V.；杰皮，M.；韦拉奇尼，C. A. 《化学物理快报》，2003年，第382卷，第518页），通过在近晶C相中的2H核磁共振光谱法，研究了铁电近晶型化合物（+）-（S）-4-[4'-(1-甲基庚氧基)]联苯4-(10-十一烯氧基)苯甲酸酯的旋转扩散系数D（平行）和D（垂直）。根据扩散常数以及分子内部和整体重排运动的活化能，对自旋-晶格弛豫时间进行了分析，并将结果与近晶A（SmA）相进行了比较。此外，根据SmA相中的2H核磁共振数据，采用一种理论方法研究了介电常数和介电弛豫时间函数。计算了复磁化率张量实部Rχγω和虚部χγω（γ = 平行，垂直）的纵向和横向分量以及类向列型旋转粘度系数λ2和λ5。
