Hi,
I am new to GULP and trying to use ReaxFF to perform MD simulation using Material Studio.
In previous step, I perform a NPT dynamics to get the proper density of the system. Then I perform NVT dynamics to equilibrate the system without assigning velocity, but the initial stage shows extremely high temperature and the trajectory shows unreasonable movement.
So I added the final velocities from the previous step of density adjustment, but by doing so the program report ERROR : charge solution failed in setreaxffQiter and I have no clue what it suggest to be.
It would be more than appreciated if anyone could provide any kind help or instruction!
Best,
Tingxuan
p.s. Sorry I can only use this method to upload the input file, as I am new user that cannot upload a file and the full file is to long which there is a length limit here 
md conv conse qok nomod pres spat pot efg qiter
ensemble nvt
tau_thermostat 0.1 ps
temperature 298.000000 K
equilibration 0.001 ps
timestep 0.1 fs
production 1 ps
write 100
sample 100
title
GULP calculation from Materials Studio for Cellubiose
end
cell
21.094300 24.041900 25.890000 92.351300 96.460200 97.279200
fractional
C1 core 0.186141 0.335796 0.120541 0.000000 1.000000 0.0 1 1 1
H1 core 0.175245 0.292751 0.132285 0.000000 1.000000 0.0 1 1 1
O1 core 0.160211 0.339541 0.066440 0.000000 1.000000 0.0 1 1 1
...
VELOCITIES
1 3.604728 -1.250909 3.044476
2 -0.595171 -3.385330 4.164299
3 3.177406 -0.598277 0.179269
...
Species
C1 core C
H1 core H
O1 core O
spacegroup
P 1
library reaxff_oxidative
dump Cellubiose.grs
output movie arc Cellubiose
mdarchive Cellubiose.arc
output trajectory Cellubiose.trg