Keyword DYNAMICS

This keyword activates Born-Oppenheimer molecular dynamics (BOMD) simulations.
Options:
STEP=$<$Real$>$ The time length of a BOMD step in fs. The default value is 1 fs.
MAX=$<$Integer$>$ The number of BOMD steps in the simulation. This value must be specified.
INT=$<$Integer$>$ Step interval to update deMon.out file. The default value is 10.
R=$<$Real$>$ The radius of an Anderson containment sphere.
Description:
Note that DYNAMICS requires MAX to be specified, even though it has the syntax of an option. A BOMD step in deMon2k consists of solving the time-independent electronic Schrödinger equation to get the forces on the nuclei, followed by a classical velocity Verlet [220,221] propagation of the nuclei according to those forces. For each BOMD step, the step time, molecular energies, atomic coordinates, and velocities are written to the trajectory file deMon.trj. The BOMD time step and the number of those steps are defined by the options STEP and MAX, respectively. The INT option controls the updating of the deMon.out and deMon.mol files. It specifies the step interval after which data are written to those two files. By default, the deMon.out file records the time and the instantaneous temperature as well as the instantaneous kinetic, potential, and total energies. It also records averages of temperature and (total) energy. The deMon.mol file records only energies (see 4.7.3 for energy selection) and atomic coordinates for visualization of the BOMD propagation with MOLDEN (see 4.10.1). Please note that the number of propagation steps in the animation is limited by your specific MOLDEN implementation. The R option of the DYNAMICS keyword activates an Anderson containment sphere [221]. It bounces particles back into its center under energy and (linear) momentum conservation. The radius of the containment sphere is defined in Ångström or Bohr according to the unit setting in the GEOMETRY keyword (see 4.1.1).