Forcite COMPASS II Charge | Dassault Systèmes®

VN 2022-01-26

Hello all,

I am using sketch and Geometry Optimization to optimize two systems NaCl and Zn(ClO4)2 using Forcite module with COMPASSII forcefield, and got some results:

For NaCl: The charges of Na+ and Cl- are assigned as +1 and -1, respectively before the optimization, and they are unchanged after the optimization.
For Zn(ClO4)2: The charges of Zn2+ and O- are assigned +2 and -1, respectively before the optimization, but they becomes 0 and -0.6020 after the optimization. Why is that? I expect that the charge of Zn2+ should not be changed after the optimization. You can see below details. I would appreciate any explanation and suggestion.

NaCl: #----------------------------------------------------------------------------

#topology

Zn(ClO4)2:#---------------------------------------------------------------------------------------

#topology

@column 1 element
@column 2 atom_type
@column 3 charge_group
@column 4 isotope
@column 5 formal_charge
@column 6 charge
@column 7 switching_atom
@column 8 oop_flag
@column 9 chirality_flag
@column 10 occupancy
@column 11 xray_temp_factor
@column 12 connections

@molecule Sketch1

XXXX_1:O1 O o1-q ? 0 1- -0.6020 0 0 8 1.0000 0.0000 Cl1/1.5
XXXX_1:Cl1 Cl cl4 ? 0 0 1.4080 0 0 8 1.0000 0.0000 O1/1.5 O2/1.5 O3/1.5 O4/1.5
XXXX_1:O2 O o1-q ? 0 0 -0.6020 0 0 8 1.0000 0.0000 Cl1/1.5
XXXX_1:O3 O o1-q ? 0 0 -0.6020 0 0 8 1.0000 0.0000 Cl1/1.5
XXXX_1:O4 O o1-q ? 0 0 -0.6020 0 0 8 1.0000 0.0000 Cl1/1.5
XXXX_1:Zn1 Zn zn+2 ? 0 2+ 0.0000 0 0 8 1.0000 0.0000
XXXX_1:O5 O o1-q ? 0 1- -0.6020 0 0 8 1.0000 0.0000 Cl2/1.5
XXXX_1:Cl2 Cl cl4 ? 0 0 1.4080 0 0 8 1.0000 0.0000 O5/1.5 O6/1.5 O7/1.5 O8/1.5
XXXX_1:O6 O o1-q ? 0 0 -0.6020 0 0 8 1.0000 0.0000 Cl2/1.5
XXXX_1:O7 O o1-q ? 0 0 -0.6020 0 0 8 1.0000 0.0000 Cl2/1.5
XXXX_1:O8 O o1-q ? 0 0 -0.6020 0 0 8 1.0000 0.0000 Cl2/1.5
#-----------------------------------------------------------------------------------------------------------------------

Best,

Trang