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Patterns with High Rhythmicity Levels in Multicomponent Liesegang Systems
Author(s) -
Msharrafieh Maysam,
Sultan Rabih
Publication year - 2005
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200500199
Subject(s) - multiplet , chemistry , bifurcation , aperiodic graph , precipitation , rhythm , chemical physics , crystallography , salt (chemistry) , physics , mathematics , spectral line , combinatorics , quantum mechanics , nonlinear system , astronomy , meteorology , acoustics
Liesegang banding is the display of rhythmic strata of precipitate as co‐precipitate ions interdiffuse in a gel medium. Complex periodic patterns as well as aperiodic structures could emerge, notably in systems where more than one salt is precipitated. The use of three cations (Co 2+ , Ni 2+ , and Mg 2+ ) in the banded precipitation of their hydroxides resulted in an unusual pattern with a consistently increasing rhythmicity. A periodic structure marked by the succession of band multiplets with increasing number of bands (from singlets to doublets to triplets to quadruplets, consistently) was observed. Such rhythmic patterns are obtained as the initial Mg 2+ concentration ([Mg 2+ ] 0 ), chosen as a control parameter, increases through a critical value. At high [Mg 2+ ] 0 , the trend breaks after a long time elapses. Two types of bifurcation are therefore experienced by such a system: concentration bifurcation and diffusive (time/space) bifurcation. The dynamics is elucidated on the basis of an analysis of the bands in certain groups, and gel regions between these groups, as well as between group blocs (here, a bloc denotes a succession of multiplet groups, with repetitively the same number of bands). Finally, similarities between our system and naturally occurring rhythmic patterns are emphasized and discussed.