TIP$P water model (fwd)

From: Vemparala Satyavani <vani "-at-" reef.phys.lsu.edu>
Subject: TIP$P water model (fwd)
Date: Thu, 18 Oct 2001 12:17:13 -0500 (CDT)

 Hi,
 Thanks for all the help regarding my previous query. I incorporated the
 TIP4P model. I have one question regarding the constraints in this model
 of water.
 To avoid the dynamics on the dummy particle ( as suggested in the GROMACS
 site, thanks to David Va der Spoel and Paul van Maaren), iam
 redistribuiting the forces on the dummy to the other three atoms. To do
 this every time step, i compute the positions of the dummy particle before
 passing all the coordinates to Ewald method.
 For the constraints part, i still have constraints only on OH, OH and HH
 bond. Do i need constraints between dummy particle(M) and other three
 atoms?
 If i don't want to use the rigid model, can i use a flexible model for
 TIP4P water? Can anyone give me some information about where i can get the
 parameters for the flexible model of TIP4P model of water(AMBER has
 parameters for TIP3P, i coudn't find parameters for TIP4P.)
 Thanks
 vani