[CP2K-user] [CP2K:13642] Molecular oxygen multiplicity

[Anton S. Lytvynenko]

Dear Ajay,

20.07.20 03:41, MD Simulation пише:
> Would 10 oxygens have a multiplicity of 21?  That doesn't seem right
> to me.

Why not? The multiplicity of the system is derived from the number of
the unpaired electrons. You can decrease it if you are pretty sure that
some electrons have actually paired (typically in result of a bond
formation). However, it is probably not true in the initial point of
your calculation.

If you are unsure, you can also try RELAX_MULTIPLICITY option to deduce
the value from the first principles. However, this may add another
degree of instability in your SCF convergence. Maybe convergence to some
reasonable multiplicity followed by reconvergence with the relaxed one
could help.

Theoretically, this approach could also help you in further modeling, as
the multiplicity of the system will change during the process (I
understand that spin chemistry is more complicated, though).

Yours,

Anton