CHARMM dummy atoms

[Rick Venable <rvenable$at$pollux.cber.nih.gov>]

 An aside: those with CHARMM related questions may wish to try the web
 based bulletin board system at www.charmm.org   A number of developers
 and advanced users participate regularly.
 On Thu, 1 Apr 2004 martin$at$yangtze.hku.hk wrote:
 > I would like to consult about how to add two or more dummy atoms in
 > Charmm?
 Dummy atoms are used for a variety of purpose, and can be assigned
 arbitrary properties by editing RTF and PARAM files if needed.  It
 really depends on how you want to use these dummy atoms.  There is an
 existing DUM atom type in several of the distributed RTF/PARAM file
 pairs.
 > Actually, I am calculating a system with 2 segments. I would like
 > to introduce constant velocity to 1 segment (all the atoms in segment
 > move in one direction with same spped).
 >
 > How can I do so?
 Modify the velocities in a dynamics restart file; they are listed for
 each atom in PSF order, which is the same ordering as that in the
 corresponding CHARMM .crd file.
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 Rick Venable           29/500
 FDA/CBER/OVRR Biophysics Lab
 1401 Rockville Pike    HFM-419
 Rockville, MD  20852-1448  U.S.A.
 (301) 496-1905   Rick_Venable$at$nih.gov
 ALT email:  rvenable$at$speakeasy.org
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