Multi-heat bath molecular dynamics

OpenMX Ver. 3.8 supports a multi-heat bath molecular dynamics simulation where temperature of each grouped atom is controlled with a heat-bath by a velocity scaling scheme [19]. The method is performed by the following keyword:

    MD.Type          NVT_VS4

The number of groups is specified by

    MD.num.AtomGroup    2

and the groups are defined by

    <MD.AtomGroup
      1  1 
      2  1
      3  1
      4  2
      5  2
    MD.AtomGroup>

The beginning of the description must be '$<$MD.AtomGroup', and the last of the description must be 'MD.AtomGroup$>$'. The first column is a sequential serial number for identifying atoms. The second column is an identification number for each atom, representing the group to which the atom belongs. The identification number has to be specified from 1, and followed by 2, 3, $\cdots$. The above is an example where only five atoms are involved in the system and there are two groups. In Ver. 3.8, the profile of temperature for all the groups is controlled by the keyword 'MD.TempControl' as discussed in the subsection 'NVT molecular dynamics by a velocity scaling'. In the feature release, we will support a functionality that temperature is independently controlled for each group.