In this study, we theoretically investigate microscopic mechanism of the SCN vibrational frequency fluctuations of 2-nitro-5-thiocyanate benzoic acid (NTBA) in H₂O by classical molecular dynamics simulation. Based on the vibrational solvatochromic theory, the decay components in the frequency-frequency time correlation function (FFTCF) of NTBA in H₂O are characterized with time constants of 0.13 ps and 1.43 ps. We find the hydration structure and water dynamics in the vicinity of the vibrational probe of NTBA are similar to those in bulk. We consider that the electrostatic interactions with “bulk-like” water molecules around NTBA induce the slow decay component (i.e. 1-ps decay component) of the FFTCF of NTBA in H₂O.

在这项研究中，我们从理论上通过经典的分子动力学模拟研究了2-硝基-5-硫代氰酸苯甲酸（NTBA）在H ₂ O中SCN振动频率波动的微观机理。基于振动溶变色理论，NTBA在H ₂ O中的频率-频率时间相关函数（FFTCF）中的衰减分量具有0.13 ps和1.43 ps的时间常数。我们发现，NTBA振动探针附近的水合结构和水动力学与散装的相似。我们认为与NTBA周围的“大块状”水分子的静电相互作用会诱导H ₂中NTBA的FFTCF的缓慢衰减分量（即1-ps衰减分量）。哦