modified potential. Using:
\beq
\phi' = \left(\phi-\phi_0\right) ~{\rm MOD}~ 2\pi
+\label{eqn:dphi}
\eeq
where $\phi_0$ is the reference angle, the potential is defined as:
\beq
2 1 1000 0 1000 ; Restrain to a line (Y-axis)
3 1 1000 0 0 ; Restrain to a plane (Y-Z-plane)
+[ dihedral_restraints ]
+; ai aj ak al type label phi dphi kfac power
+ 3 6 1 2 1 1 180 0 1 2
+ 1 4 3 5 1 1 180 0 1 2
+
; Include TIP3P water topology
#include "amber99/tip3p.itp"
The reference positions are read from a
separate coordinate file by {\tt \normindex{grompp}}.
+
+{\bf {\tt [~dihedral_restraints~]} :} restrain selected dihedrals to a reference value.
+The implementation of dihedral restraints is described in section \ssecref{dihedralrestraint} of the manual.
+The parameters specified in the [dihedral_restraints] directive are as follows:
+\begin{itemize}
+\item {\tt type} has only one possible value which is 1
+\item {\tt label} is unused and has been removed from the code.
+\item {\tt phi} is the value of $\phi_0$ in \eqnref{dphi} and \eqnref{dihre} of the manual.
+\item {\tt dphi} is the value of $\Delta\phi$ in \eqnref{dihre} of the manual.
+\item {\tt kfac} is analogous to {\tt fac} in the implementation of distance restraints. It is the factor by which the force constant is multiplied. By doing so, different restraints can be maintained with different force constants.
+\item {\tt power} is unused and has been removed from the code.
+\end{itemize}
+
{\bf {\tt \#include "tip3p.itp"} :} includes a topology file that was already
constructed (see section~\ssecref{molitp}).