Difference between revisions of "United-atom model"

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the carbon atoms and are not expressed explicitly. Many [[force fields]]
 
the carbon atoms and are not expressed explicitly. Many [[force fields]]
 
make use of this approximation in order to reduce the computational  
 
make use of this approximation in order to reduce the computational  
overheads.
+
overheads. For example, ''n''-hexane consists of 6 carbon atoms and
 +
14 hydrogen atoms. A fully-atomistic model of ''n''-hexane would
 +
require 20 interaction sites. Using the united-atom approximation, this reduces to
 +
two <math>CH_3</math> sites and four <math>CH_2</math> sites, a significant reduction.
 +
==Justification==
 +
==Parameters==
 
==References==
 
==References==
 
[[Category: Models]]
 
[[Category: Models]]

Revision as of 10:44, 30 May 2007

In the united-atom model the CH_2 and CH_3 units are treated as one point, i.e. the hydrogen atoms are incorporated within the carbon atoms and are not expressed explicitly. Many force fields make use of this approximation in order to reduce the computational overheads. For example, n-hexane consists of 6 carbon atoms and 14 hydrogen atoms. A fully-atomistic model of n-hexane would require 20 interaction sites. Using the united-atom approximation, this reduces to two CH_3 sites and four CH_2 sites, a significant reduction.

Justification

Parameters

References