Bond Functions

Functional forms for bond interactions

Below are listed the interaction forms available for bonds within molecules, with energy and force equations provided in full. Parameters are listed in the input order expected by Dissolve.

Bond interaction between atoms $i$ and $j$, where the bond length is $r_{ij}$.

Keyword Parameters Description
Harmonic k
$r_{eq}$
Simple harmonic bond strech $$ E_{ij} = \frac{1}{2} k (r_{ij} - r_{eq})^2 $$ $$ F_{ij} = -k (r_{ij} - r_{eq}) $$
EPSR C'
$r_{eq}$
Harmonic bond weighted by the masses of the atoms - equivalent to that implemented in EPSR, where $ C’ = C/2$. $$ E_{ij} = C’ (r_{ij} - r_{eq})^2 / \omega $$ $$ F_{ij} = - 2 C’ (r_{ij} - r_{eq}) / \omega $$ $$ \omega = \frac{r_{eq}}{\sqrt{ \frac{m_i + m_j}{m_i m_j}}} $$
Last modified April 23, 2024: Update release notes. (70ff745)