论文标题
氢相IV的表征通过量子非难性的全面说明
Hydrogen phase-IV characterization by full account of quantum anharmonicity
论文作者
论文摘要
我们设计一个框架，即使在强量子非谐调的情况下，也可以计算分子晶体中的精确声子。我们的方法是基于从路径积分分子动力学模拟的语音哑光函数的静态极限的计算。我们的方法的差异非常低，它可以在几次核动力学后计算精确的声子频率，并且通过使用适当的约束位移操作员进一步稳定它。我们在高压下将其应用于固体。对于第三阶段，我们的预测红外（IR）和拉曼活性颤音与实验非常吻合。然后，我们通过与振动数据进行直接比较来表征第四相的结晶对称性，并确定其拉曼和IR vibron峰的特征。
We devise a framework to compute accurate phonons in molecular crystals even in case of strong quantum anharmonicity. Our approach is based on the calculation of the static limit of the phononic Matsubara Green's function from path integral molecular dynamics simulations. Our method enjoys a remarkably low variance, which allows one to compute accurate phonon frequencies after a few picoseconds of nuclear dynamics, and it is further stabilized by the use of appropriate constrained displacement operators. We applied it to solid hydrogen at high pressure. For phase III, our predicted infrared (IR) and Raman active vibrons agree very well with experiments. We then characterize the crystalline symmetry of phase IV by direct comparison with vibrational data and we determine the character of its Raman and IR vibron peaks.
