@article{oai:kanazawa-u.repo.nii.ac.jp:00011140,
 author = {木原, 國昭 and Kihara, Kuniaki},
 journal = {The science reports of the Kanazawa University = 金沢大学理科報告},
 month = {Jan},
 note = {Computer programs were prepared for analyzing the atom trajectories generated in molecular dynamics simulation (MDS), and applied to reinterpret the mechanism of the α-β polymorphic transition in quartz (SiO₂). The programs contain the parts for calculating atomic quantities such as bond distances, angles and mean square displacements, and for collective ones such as X-ray scattering intensities, power spectral densities and normal modes. With the aid of a simplified structure model composed of atom sites of double-minimum potentials, the atomic mechanism of the α-β transition in quartz generated in the simulations was successfully interpreted. A transfer mode, in which atoms can move over the energy barriers between the double-minimum wells, is excited as an extra mode with an optic character even in the low-temperature phase (α), and the α-β transition is driven by the softening of this mode. The strong softening of this mode near the transition point also causes, via mode coupling, the softening of the two transversal acoustic branches with low frequencies in some ranges of small wave vector q in Γ-M, which cause the characteristic diffuse scattering and may cause the incommensurate satellite reflections observed when temperature approaches to the transition point.},
 pages = {55--80},
 title = {On the analysjs of collective motions of atoms in mineral structures, and the mechanism of the α-β polymorphic transition in quartz},
 volume = {53},
 year = {2009}
}