Interstitial water of forsterite has a unique high-density structure. To investigate the structures and diffusive properties of interstitial water, we performed molecular dynamics calculations of thin water layers in forsterite in crystalline and glassy states. The results show that the density of interstitial water of forsterite in both crystalline and glassy states increases as the thickness of the water layer decreases at <3 nm. The self-diffusion coefficient of water decreases with the densification. Furthermore, it was found that the mobility of atoms in forsterite increases with the increase of the thickness of the water layer. The motion of interstitial water may propagate the motion of atoms in forsterite. The results suggest that the interstitial water of forsterite has effects to promote rearrangements of atoms in coexisting minerals and plays an important role in mineral evolutions.

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镁橄榄石及其间隙水的结构和动力学

镁橄榄石的间隙水具有独特的高密度结构。为了研究间隙水的结构和扩散特性，我们对结晶态和玻璃态的镁橄榄石中的薄水层进行了分子动力学计算。结果表明，晶态和玻璃态镁橄榄石间隙水的密度随着水层厚度减小（<3 nm）而增加。水的自扩散系数随着致密化而降低。此外，还发现镁橄榄石中原子的迁移率随着水层厚度的增加而增加。间隙水的运动可以传播镁橄榄石中原子的运动。研究结果表明，镁橄榄石间隙水具有促进共生矿物原子重排的作用，在矿物演化中发挥着重要作用。