This is part of the bias module |
Adds harmonic and/or linear restraints on one or more variables.
Either or both of SLOPE and KAPPA must be present to specify the linear and harmonic force constants respectively. The resulting potential is given by:
\[ \sum_i \frac{k_i}{2} (x_i-a_i)^2 + m_i*(x_i-a_i) \]
.
The number of components for any vector of force constants must be equal to the number of arguments to the action.
Additional material and examples can be also found in the tutorial lugano-2
The following input tells plumed to restrain the distance between atoms 3 and 5 and the distance between atoms 2 and 4, at different equilibrium values, and to print the energy of the restraint
Quantity | Description |
bias | the instantaneous value of the bias potential |
force2 | the instantaneous value of the squared force due to this bias potential |
SLOPE | ( default=0.0 ) specifies that the restraint is linear and what the values of the force constants on each of the variables are |
KAPPA | ( default=0.0 ) specifies that the restraint is harmonic and what the values of the force constants on each of the variables are |
AT | the position of the restraint |
ARG | the arguments on which the bias is acting. You can use multiple instances of this keyword i.e. ARG1, ARG2, ARG3... |