Lattice dynamics of coesite

Re - examination of " P 21 / a coesite "

Kirfel, Will, and Arndt (1979) reported a quenchable new phase of Si02, synthesized in aqueous solution at 4449 kbar and 6100 C, having the space group P21/a and a crystal structure closely related to coesite. However, single-crystal X-ray and TEM studies have revealed that their observations could be the result of (100)-twinning of C2/e coesite. Therefore, a distinct P2da phase probably does n...

The influence of OH in coesite on the kinetics of the coesite-quartz phase transition

Coesite is an important pressure indicator for metamorphic rocks of ultra-high pressure origin. However, it often does not survive exhumation, but reacts back to quartz. Although it was shown experimentally that hydrogen incorporation in coesite increases with increasing pressure, the few coesite relics, which are found in nature, are “dry”. Thus, does the incorporation of hydrogen promote the ...

Lattice Dynamics of Tetracyanoethylene

Dynamics of lattice kinks

We consider a class of Hamiltonian nonlinear wave equations governing a field defined on a spatially discrete one dimensional lattice, with discreteness parameter, d = h, where h > 0 is the lattice spacing. The specific cases we consider in detail are the discrete sine-Gordon (SG) and discrete φ models. For finite d and in the continuum limit (d → ∞) these equations have static kink-like (heter...

An & srmonic & lattice Dynamics

'A. H. Wilson, Theory ofMetals, 2nd ed. (Cambridge U. P., Cambridge, England, 1953). "I.Nebenzahl and M. Weger, Philos. Mag. 24, 1119(1971). 2'C. Herring, Phys. Rev. 96, 1163 (1954). C. Herring, Semiconductors and Phosphors, edited by M. Schon and H. Welker (Vieweg, Braunschweig, Germany, 1958), p. 184. "P. Eklund (private communication). "H. Van Cong and G. Mesnard, Phys. Status Solidi 8 50, 5...