Time step in femtoseconds. This is the long time step in case of the double time step algorithm.
Default: 2 fs.
How many MD steps to run.
Double time step algorithm by Tuckerman et al.
<number> is the number
of short time steps in one long. The keyword cannot be used simultaneously
Constrain <toler> <i_1> <i_2> <i_3> .... <i_ntypes>
Use SHAKE algorithm to constrain the bond lengths. The option cannot be used
<toler> is the tolerance level.
<i_1> <i_2> ... <i_ntypes> are numbers 0 or 1, which specify
whether (1) or not (0) to apply constraints to molecules of each species.
Cut-off (in Å) for the Lennard-Jones and real-space part of the electrostatic forces.
Default: 12 Å
Cut-off (in Å) for Lennard-Jones forces computed each short-time step (has an effect only in double-time step algorithm)
Default: 5 Å
Update the list of neighbors (Verlet list) every
Electrostatics <type> [<A> <B>]
How to treat electrostatics
<type> may be Ewald (default), RF (reaction field) and Cutoff
For Ewald: A is , where is the Ewald convergence parameter. Precision of the real-space Ewald part is determined by . defines the number of terms in the reciprocal part. It cuts the reciprocal series when expression in the exp of the reciprocal part exceeds . Recommended values A = 2.5 - 3; B = 7 - 10.
For reaction field, A is the dielectric permittivity and B is the Debye screening length in Å. Setting the Debye length to 0 means an infinite Debye length, i.e non-conducting solution.
<type> is ``Cutoff'', parameters and are not necessary, and
no special treatment of electrostatic forces out of takes place.
Default: Ewald method with A=2.8 and B=9.
If this option is specified and the absolute force acting on any atom
exceeds the specified
<value>, the force will be cut to this level while
maintaining the direction. The value is given in Å and has a sense
of the maximum allowed additional displacement during one time step
( F*dt**2/m ) caused by this force
Default: Do not cut forces
Use another (than Lorentz-Berthelot) combination rule for Lennard-Jones parameters for different types
type may be one of the following:
Sigma_geom - LJ parameter is calculated as a geometrical
average of the both types (as for example in the OPLS force field)
Kong - use Kong rules (J.Kong, J.Chem.Phys., 59, 2464, (1973))
Default: use Lorentz-Berthelot combination rules
Bind_atoms <file> <deviation>
If this keyword is specified, atoms defined in file
<file> will be
bound to corresponding positions (given in the same file) by a
harmonic potential with characteristic deviation given by