Cylindrical system

From Online Dictionary of Crystallography

Revision as of 08:50, 12 May 2006 by AndreAuthier (Talk | contribs)
Jump to: navigation, search

Système cylindrique (Fr) Sistema cylindrico (It).

Definition

The cylindrical system contains non-crystallographic point groups with one axis of revolution (or isotropy axis). There are five groups in the spherical system:

Hermann-Mauguin symbol Short Hermann-Mauguin symbol Schönfliess symbol order of the groupgeneral form
 A_\infty \infty C_\infty  \infty rotating cone
 {A_\infty \over M}C  {\bar \infty} C_{\infty h} \equiv S_{\infty} \equiv C_{\infty i}  \infty rotating finite cylinder
 A_\infty \infty A_2  \infty 2 D_{\infty }  \infty finite cylinder
submitted to equal and
opposite torques
 A_\infty M \infty m C_{\infty v}  \infty stationary cone
 {A_\infty \over M} {\infty A_2 \over \infty M} C  {\bar \infty}m \equiv {\bar \infty} {2\over m} D_{\infty h} \equiv D_{\infty d}  \infty stationary finite cylinder



CylindricalSystem.gif

Note that  A_\infty M represents the symmetry of a force, or of an electric field and that  {A_\infty \over M}C represents the symmetry of a magnetic field (Curie 1894), while  {A_\infty \over M} {\infty A_2 \over \infty M} C represents the symmetry of a uniaxial compression.

History

The groups containing isotropy axes were introduced by P. Curie (1859-1906) in order to describe the symmetry of physical systems (Curie P. (1884). Sur les questions d'ordre: répétitions. Bull. Soc. Fr. Minéral., 7, 89-110; Curie P. (1894). Sur la symétrie dans les phénomènes physiques, symétrie d’un champ électrique et d’un champ magnétique. J. Phys. (Paris), 3, 393-415.).

See also

Curie laws
spherical system
Section 10.1.4 of International Tables of Crystallography, Volume A
Section 1.1.4 of International Tables of Crystallography, Volume D