********>Bugfix 49:
Author: Ray Luo
Date: 08/17/2005

Programs: pbsa

Description: The program outputs highly fluctuating reaction field energies
             when the net charges of "neutral" systems are close to
             but not equal to zero. This is due to the failure in scaling
             solvent-induced surface charges in such situations.

Fix: Apply the following patch to amber8/src/pbsa/pb_force.f

------------------------------------------------------------------------------
*** pb_force.f  2004-03-13 22:21:24.000000000 -0800
--- pb_force.f  2005-08-25 11:28:09.646492724 -0700
***************
*** 459,465 ****
     !_PBREAL_ gci, gcj1, gcj2, gcj3, gcj4, gcj5, gcj6, gcj7, gcj8
     !_PBREAL_ gcij(27)

!    _PBREAL_, parameter :: smallcrg = 0.0001d0
      
     ! initialization
      
--- 459,465 ----
     !_PBREAL_ gci, gcj1, gcj2, gcj3, gcj4, gcj5, gcj6, gcj7, gcj8
     !_PBREAL_ gcij(27)

!    _PBREAL_, parameter :: smallcrg = 0.5d0
      
     ! initialization
      
------------------------------------------------------------------------------

Temporary workaround: You can avoid this bug by forcing the net charges of 
neutral systems zero within rounding error.