School of Space Science and Physics, Shandong University, Weihai, 264209, China.
ICQD, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, 230026, China.
Sci Rep. 2016 Jul 4;6:29273. doi: 10.1038/srep29273.
The vibrational spectrum of ice XI at thermal wavelengths using the CASTEP code, a first-principles simulation method, is investigated. A dual-track approach is constructed to verify the validity for the computational phonon spectrum: collate the simulated spectrum with inelastic neutron scattering experiments and assign the photon scattering peaks according to the calculated normal vibration frequencies. The 33 optical normal vibrations at the Brillouin center are illustrated definitely from the ab initio outcomes. The depolarizing field effect of the hydrogen bond vibrations at frequencies of 229 cm(-1) and 310 cm(-1) is found to agree well with the LST relationship. It is a convincing evidence to manifest the LO-TO splitting of hydrogen bonds in ice crystal. We attribute the two hydrogen bond peaks to the depolarization effect and apply this viewpoint to ordinary ice phase, ice Ih, which is difficult to analyse their vibration modes due to proton disorder.
利用 CASTEP 代码（一种第一性原理模拟方法）研究了热波长下冰 XI 的振动光谱。构建了一种双通道方法来验证计算声子谱的有效性：将模拟谱与非弹性中子散射实验进行对比，并根据计算出的正则振动频率来分配光子散射峰。从从头算结果中明确说明了布里渊区中心的 33 个光学正则振动。在频率为 229 cm(-1)和 310 cm(-1)的氢键振动的去极化场效应与 LST 关系吻合得很好。这是证明冰晶体中氢键的 LO-TO 劈裂的有力证据。我们将这两个氢键峰归因于去极化效应，并将这一观点应用于普通冰相冰 Ih，由于质子无序，很难分析其振动模式。
