Schella André, Mulsow Matthias, Melzer André, Schablinski Jan, Block Dietmar
Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald, Germany.
Phys Rev E Stat Nonlin Soft Matter Phys. 2013 Jun;87(6):063102. doi: 10.1103/PhysRevE.87.063102. Epub 2013 Jun 6.
The quantities entropy and diffusion are measured for two- and three-dimensional (3D) dust clusters in the fluid state. Entropy and diffusion are predicted to be closely linked via unstable modes. The method of instantaneous normal modes is applied for various laser-heated clusters to determine these unstable modes and the corresponding diffusive properties. The configurational entropy is measured for 2D and 3D clusters from structural rearrangements. The entropy shows a threshold behavior at a critical temperature for the 2D clusters, allowing us to estimate a configurational melting temperature. Further, the entropic disorder increases for larger clusters. Finally, the predicted relation between entropy and unstable modes has been confirmed from our experiments for 2D systems, whereas 3D systems do not show such a clear correlation.
测量了处于流体状态的二维和三维尘埃团簇的熵和扩散量。预计熵和扩散将通过不稳定模式紧密相连。应用瞬时正常模式方法对各种激光加热的团簇进行研究，以确定这些不稳定模式及相应的扩散特性。通过结构重排测量二维和三维团簇的构型熵。二维团簇的熵在临界温度下呈现阈值行为，这使我们能够估算构型熔化温度。此外，对于更大的团簇，熵无序度增加。最后，我们对二维系统的实验证实了熵与不稳定模式之间的预测关系，而三维系统并未表现出如此明显的相关性。
