To investigate the transition mechanisms of forsterite from a glassy to molten state, we performed molecular dynamics calculations in a temperature range of 10–3000 K. The results show that the thermal expansion coefficient changes remarkably at around 1567 K during heating from 10 K. This temperature is the transition point from glassy to liquid states. To investigate the mechanisms of the phase transition, shear viscosity and self-diffusion processes of atoms were analyzed. The result shows that the increasing rates of diffusion coefficients with heating change at around 1300 and 1800 K. This suggests that a diffusion mechanism changes in the supercooled liquid state. From the observation of the trajectories of atoms, it was found that atoms migrate through discontinuous hopping in the supercooled liquid matrices. The hopping probability of atoms, which is located in positions with higher Si and lower Mg densities, is higher than the average probability at low temperatures. The result indicates a dynamical correlation between the hops of atoms in the supercooled liquid state, while Brownian motion is the main mechanism of diffusion in the liquid phase at temperatures above the melting point. The mechanism of the glass–liquid transition of forsterite is important for understanding the evolution process of minerals in space.

中文翻译：

---

镁橄榄石从玻璃态到液相态的相变动力学

为了研究镁橄榄石从玻璃态到熔融态的转变机理，我们在10–3000 K的温度范围内进行了分子动力学计算。结果表明，从10 K加热时，热膨胀系数在1567 K左右发生显着变化。温度是从玻璃态到液态的转变点。为了研究相变的机理，分析了原子的剪切粘度和自扩散过程。结果表明，随着热量的增加，扩散系数的增加率在1300和1800 K左右变化。这表明，过冷液态的扩散机理发生了变化。从原子轨迹的观察，发现原子在过冷液相中通过不连续跳变迁移。处于较高Si和较低Mg密度位置的原子的跳跃概率高于低温下的平均概率。结果表明，在过冷液态下，原子跃点之间存在动力学相关性，而布朗运动是在高于熔点的温度下液相扩散的主要机理。镁橄榄石的玻璃-液体转变机理对于理解太空中矿物的演化过程非常重要。而布朗运动是在高于熔点的温度下液相扩散的主要机理。镁橄榄石的玻璃-液体转变机理对于理解太空中矿物的演化过程非常重要。而布朗运动是在高于熔点的温度下液相扩散的主要机理。镁橄榄石的玻璃-液体转变机理对于理解太空中矿物的演化过程非常重要。