Faculty of Physics, A. Mickiewicz University, Poznań, Poland.
Phys Chem Chem Phys. 2012 Mar 21;14(11):3949-59. doi: 10.1039/c2cp23668k. Epub 2012 Feb 9.
We have studied the dynamics of bis-thiourea pyridinium chloride and bromide by means of quasielastic neutron scattering (QENS). The QENS data allow describing the geometry of the in-plane motion of the pyridinium cation and reveal that it is similar to the motion previously observed in bis-thiourea pyridinium iodide. Molecular dynamics (MD) simulations have been performed to investigate the cation dynamics on the high temperature phase of the full series of compounds: bis-thiourea pyridinium chloride, bromide and iodide. Three different models of intermolecular potential have been tested and the agreement between the simulated and experimental elastic incoherent structure factors (EISFs) is used to select the more realistic one. The detailed analysis of the MD results indicates that Coulombic interactions together with the formation of hydrogen bonds between the pyridinium cation and the host sublattice influence strongly the geometry of the in-plane cation reorientation.
我们通过准弹性中子散射（QENS）研究了双硫脲吡啶鎓氯化物和溴化物的动力学。QENS 数据允许描述吡啶鎓阳离子面内运动的几何形状，并表明它类似于先前在双硫脲吡啶鎓碘化物中观察到的运动。为了研究全系列化合物：双硫脲吡啶鎓氯化物、溴化物和碘化物的高温相上的阳离子动力学，进行了分子动力学（MD）模拟。测试了三种不同的分子间势能模型，并使用模拟和实验非弹性不相干结构因子（EISF）之间的一致性来选择更现实的模型。对 MD 结果的详细分析表明，库仑相互作用以及吡啶鎓阳离子与主体子晶格之间氢键的形成强烈影响面内阳离子重取向的几何形状。
