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[资源] Angew. Chem.最新文章：晶体结构预测

Every year thousands of new crystal structures are determined
and many of these are molecular crystal structures.
However, while an enormous amount of structural data is
available, it has proven rather difficult to predict molecular
crystal structures given only the structural formula. As with
all chemical transformations, a change in energy is the driving
force underlying the formation of any crystal, and both kinetic
as well as thermodynamic contributions are important.
Molecular crystals are held together primarily by dispersion
forces which are comparatively weak and notoriously difficult
to calculate accurately. In 1994 in a seminal paper entitled
“Are Crystal Structures Predictable?” Gavezotti stated a clear
“No” and pointed out that the small energy differences
between hypothetical crystal structures are the limiting factor
for successful crystal structure predictions.[1]
Since then, this dogma has been challenged numerous
times, most prominently by a series of blind tests organized by
the Cambridge Crystallographic Data Centre (CCDC). So far
a total of five such blind tests have been organized and the
crystal structure predictions have become more accurate,
despite increased challenges posed by the organizers.[2] For
these tests a small number of organic compounds are selected
with hitherto unpublished crystal structures. The participants
are asked to propose three candidate crystal structures for
each compound which are matched against the secret
experimental crystal structures. For the latest series, which
was concluded in 2010, the results have been submitted and
analyzed but not yet published. This study included six
categories of increasing complexity and, for the first time, it
also included systems with known polymorphism and more
flexible molecules

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