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The nature of excitations in liquids has been a subject of debate for a long time. In liquids, phonons are extremely short-lived and marginalized. Instead, recent research results indicate that local topological or configurational excitations (anankeons) are the elementary excitations in high temperature metallic liquids. Local topological excitations are those which locally alter the atomic connectivity network by cutting or forming atomic bonds, and are directly tied to the atomistic origin of viscosity in the liquid. The local potential energy landscape (PEL) of anankeons represents the probability weighted projection of the global PEL to a single atom. The original PEL is an insightful concept, but is highly multi-dimensional and difficult to characterize or even to visualize. A description in terms of the local PEL for anankeons appears to offer a simpler and more effective approach toward this complex problem. At the base of these advances, is the recognition that atomic discreteness and the topology of atomic connectivity are the most crucial features of the structure in liquids, which current nonlinear continuum theories cannot fully capture. These discoveries could open the way to the explanation of various complex phenomena in liquids, such as atomic transport, fragility, and the glass transition, in terms of these excitations.

We perform a simulation of the structural phase-transition pathway under compression and dynamic properties in liquid germania (GeO₂). The structure of liquid GeO₂ is clarified through the pair radial distribution function (PRDF), distribution of GeO${}_x$$(x=4,5,6)$ units, bond angle and length distribution, and three-dimensional (3D) visualization. The result shows that the structure of liquid GeO₂ is built by GeO₄, GeO₅ and GeO${}_6$units, which are linked to each other via common oxygen atoms. The GeO${}_x$ units lead to form into the separate GeO₄-, GeO₅- and GeO₆-phases. The existence of separate phases is evidence of dynamical heterogeneity (DH) in liquid GeO₂. The atoms in GeO₅-phase are more mobile compared to other ones. The variation of the self-diffusions of Ge and O atoms under pressure is examined via the characteristics of separate GeO₄-, GeO₅- and GeO₆-phases. We found that under compression, there is diffusion anomaly in liquid GeO₂. This is suggested to be related to the very high mobility of Ge and O atoms in the GeO₅-phase compared to GeO₄- and GeO₆-phase.