Quasielastic neutron scattering (QENS) allows measurement of the molecular displacements in time and space, from pico- to tens of nanoseconds and from Ångstroms to nanometers, respectively. The method probes dynamics from fast vibrational modes down to slow diffusive motion. Every scattering experiment leads to a dynamic structure factor \(S\left( {\vec Q,\omega } \right)\) or its spatial and temporal Fourier transform (van Hove correlation function \(G\left( {\vec r,t} \right)\)). This shows exactly where the atoms are and how they move. In this manuscript the basics of the QENS method are presented and a few examples highlighting the potentials of QENS are given: (i) diffusion of liquids and gases in nano- and mesoporous materials; (ii) hydrogen dynamics in a high temperature polymer electrolyte fuel cell (HT-PEFC) and (iii) influence of the surface interactions on polymer dynamics in nanopores.

准弹性中子散射（QENS）可以测量时间和空间上的分子位移，分别从皮秒到几十纳秒，从埃到几纳米。该方法探测从快速振动模式到慢速扩散运动的动力学。每个散射实验都会导致动态结构因子\（S \ left（{\ vec Q，\ omega} \ right）\）或其时空傅立叶变换（van Hove相关函数\（G \ left（{\ vec r ，t} \ right）\））。这准确地显示了原子在哪里以及它们如何移动。在本手稿中，介绍了QENS方法的基础，并列举了一些突出QENS潜力的例子：（i）液体和气体在纳米和中孔材料中的扩散；（ii）高温聚合物电解质燃料电池（HT-PEFC）中的氢动力学，以及（iii）表面相互作用对纳米孔中聚合物动力学的影响。