|
|
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| V_{tors} \left(\phi\right) = \sum_{i=0}^n b_i \cos \left( i \phi \right) | | V_{tors} \left(\phi\right) = \sum_{i=0}^n b_i \cos \left( i \phi \right) |
| </math> | | </math> |
| | |
| | == Van der Waals intramolecular interactions == |
Revision as of 13:43, 22 February 2007
Modelling of internal degrees of freedom, usual techniques:
Bond distances
- Atoms linked by a chemical bond (stretching):
Bond Angles
Bond sequence: 1-2-3:
Bond Angle:
Two typical forms are used to model the bending potential:
Dihedral angles. Internal Rotation
Bond sequence: 1-2-3-4
Dihedral angle () definition:
Consider the following vectors:
- ; Unit vector in the direction of the 2-3 bond
- ; normalized component of ortogonal to
- ; normalized component of ortogonal to
For molecules with internal rotation degrees of freedom (e.g. n-alkanes), a torsional potential is
usually modelled as:
or
Van der Waals intramolecular interactions