inconsistent vdWaals-parameters Force field parameters for element CA

Hi all,

I want to use ReaxFF force field to simulate the oxidation of β-isophorone with the presence of Cu-Salen as a catalyst. I got a force field that contains the elements of my simulation(C/H/O/N/Cu).

Psofogiannakis G M, Mccleerey J F, Jaramillo E, et al. ReaxFF Reactive Molecular Dynamics Simulation of the Hydration of Cu-SSZ-13 Zeolite and the Formation of Cu Dimers[J]. Journal of Physical Chemistry C, 2015, 119(12):6678-6686. (CHONSSiCaCsKSrNaMgAlCu.ff)

And when I run the simulation, I got warnings like this:

Warning: inconsistent vdWaals-parameters
Force field parameters for element CA
indicate inner wall+shielding, but earlier
atoms indicate different vdWaals-method.
This may cause division-by-zero errors.
Keeping vdWaals-setting for earlier atoms.

Warning: changed valency_val to valency_boc for X

I don’t understand what “CA” means.(Ca?) Do these warnings mean that this force field is not suitable for my simulation?

Thank you very much.

Luyi Ji

2017-07-07 16:06 GMT+02:00 <[email protected]>:

Hi all,

I want to use ReaxFF force field to simulate the oxidation of β-isophorone
with the presence of Cu-Salen as a catalyst. I got a force field that
contains the elements of my simulation(C/H/O/N/Cu).

Psofogiannakis G M, Mccleerey J F, Jaramillo E, et al. ReaxFF Reactive
Molecular Dynamics Simulation of the Hydration of Cu-SSZ-13 Zeolite and the
Formation of Cu Dimers[J]. Journal of Physical Chemistry C, 2015,
119(12):6678-6686. (CHONSSiCaCsKSrNaMgAlCu.ff)

And when I run the simulation, I got warnings like this:

Warning: inconsistent vdWaals-parameters
Force field parameters for element CA
indicate inner wall+shielding, but earlier
atoms indicate different vdWaals-method.
This may cause division-by-zero errors.
Keeping vdWaals-setting for earlier atoms.

Warning: changed valency_val to valency_boc for X

I don't understand what "CA" means.(Ca?) Do these warnings mean that this
force field is not suitable for my simulation?

Most ReaxFF force field files are full of junk from other
parameterizations, such as parameterizations for other elements and other
versions of ReaxFF. If they don't involve elements you are interested in,
they should be safe to ignore.

But Re:junk: the force field you are intending to use is most definitely
not a "CHONSSiCaCsKSrNaMgAlCu" force field. If you look at the abstract of
the paper you mentioned, it says: "A new Cu/Si/Al/O/H reactive ReaxFF force
field was developed". All other elements that might be present in the force
field file are therefore not part of this parameterization, and it is
unclear to what extent simulations involving them make any sense.

Kristof