Deciphering helix assembly in the heliconical nematic phase via tender resonant X-ray scattering
Deciphering helix assembly in the heliconical nematic phase via tender resonant X-ray scattering
复制标题
通过温柔的共振 X 射线散射破译螺旋向列相中的螺旋组装
DOI：
10.1039/d1tc02027g
复制
发表时间：
2021-07-01
影响因子：
6.4
通讯作者：
Liu, Feng
中科院分区：
文献类型：
--
作者：
Cao, Yu;Feng, Jun;Liu, Feng
作为单轴向列和手性向列之间的联系，扭转弯曲向列（N-TB）作为理解手性生成的关键，在过去十年中一直是一个有趣的研究课题。对螺旋结构共振效应的准确描述和理解提供了超越位置排序的相位行为的关键知识。我们通过硫k边的弱共振x射线散射（TReXS）研究了N（TB）中共振效应的表现。我们首次定量地证明了N-TB相散射峰的能量依赖关系遵循x射线吸收测量的复折射率的能量依赖关系。利用分子能量计算，从杂化的角度分析了对称/非对称二聚体的螺旋节距变化趋势，揭示了氧取代硫原子对螺旋节距和热螺旋延伸的强烈影响。
Being a link between a uniaxial nematic and a chiral nematic, the twist bend nematic (N-TB) has been an intriguing topic for research over the last decade as a key to understanding chirality generation. Accurate description and understanding of resonance effects in helical structures provide crucial knowledge on the phase behavior beyond positional ordering. We examined the manifestation of resonance effects in N(TB)via tender resonant X-ray scattering (TReXS) at the sulfur K-edge. For the first time we demonstrate quantitatively that the energy dependence of the scattering peak in the N-TB phase follows the energy dependence of the complex refractive indices measured by X-ray absorption. Taking advantage of molecular energy calculation, we decipher the distinct helical pitch variation trend for symmetric/asymmetric dimers from the perspective of hybridization and reveal the strong effect of substituting oxygen for sulfur atoms on the helical pitch and the thermal helix extension.