The experimental appearance sequence of facets of crystallographic forms on the surface of sucrose spherical monocrystals fits well the decreasing order of their absolute growth rates under the same experimental conditions. The validity of this relationship is also confirmed: (a) by experimental sphere growth from solutions doped with raffinose where the appearance sequence is inverted since the impurity inverts the order of the absolute rates; (b) by the holographic analysis of the growth of the non-polar {h0l} zone of sucrose cylindric monocrystals. Holography shows the growth fringe concentration around the spherical surface portion where the most rapid faces grow. A satisfactory interpretation of the experimental results is given on the basis of a new model which explains the growth of each single (hkl) face as the results of the two processes of step generation on the surface and normal growth at the interphase of stepped and rough surface fractions around the [hkl] pole. © 1993.
Faceting of spherical and cylindrical monocrystals of sucrose
SGUALDINO, Giulio;VACCARI, Giuseppe;MANTOVANI, Giorgio;
1993
Abstract
The experimental appearance sequence of facets of crystallographic forms on the surface of sucrose spherical monocrystals fits well the decreasing order of their absolute growth rates under the same experimental conditions. The validity of this relationship is also confirmed: (a) by experimental sphere growth from solutions doped with raffinose where the appearance sequence is inverted since the impurity inverts the order of the absolute rates; (b) by the holographic analysis of the growth of the non-polar {h0l} zone of sucrose cylindric monocrystals. Holography shows the growth fringe concentration around the spherical surface portion where the most rapid faces grow. A satisfactory interpretation of the experimental results is given on the basis of a new model which explains the growth of each single (hkl) face as the results of the two processes of step generation on the surface and normal growth at the interphase of stepped and rough surface fractions around the [hkl] pole. © 1993.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
