Subject: Summary Re Parameters for MMx

From: Ken Czaplewski <[email-masked]>
Date: Fri, 16 Oct 1998 11:48:54 -0500

Hello,

Several weeks back I inquired about Re(VI) parameters for forcefield
calculations.
The following is the summary of replies I received.

"
Two sources come to mind:

1) AK (Tony) Rappe's Universal ForceField (UFF)
2) Tom Halgren's Merck Molecular ForceField (MMFF)

Of these two, MMFF is probably more accurate than UFF. There are others, of
course, but they may not have rhenium parameters. Others which may have either
explicit parameters or a function generator:

3) Allinger's MM3/MM4
4) Clark Landis' VALBOND (?)
5) Kevin Gilbert's MMX

If you are using Hyperchem, then you might be able to use MMX or MM3/MM4
parameters (if they are available). UFF uses a Lennard-Jones 12-6, and MMFF
uses
a buffered LJ 14-7 potential.

Hope this helps,
Craig
[email-masked]
"

What I have found in the meantime is that MSI's esff force field has 16
different Re parameters for different coordination and symmetry.  This info
can be found in the file esff.frc in the BioSymm forcefield library of
their software.  

The package PCMODEL from Serena software is based on the MM2 forcefield.
Two related articles are J Comput Chem 19:1167-1178,1998 which gives the
parameters, and J Phys Chem B 1997, 101, 3174-3180 about the use of this
software to model organmetalic compounds containing Re.

Hope this is helpful to those who replied stating a similar interest in Re
parameters.

Ken