[DFTB-Plus-User] bulk water simulation

[Theodoros Leontiou]

Dear dftb+ experts,

I am interested in the MD simulation of bulk water both neutral and in 
the presence of an external uniform electric field.
I have read a number of works such as
J Phys Chem B. 114 (20), 6922-6931
and
J Phys Chem B. 115(20), 6790–6805.

My understanding is that DFTB3 must be used with damping and possibly 
dispersion. I have a question concerning the necessity of spin 
polarization. Shouldn't two unpaired electrons per oxygen atom used in 
these calculations?  My tests show that using the spin polarization 
option the effect of an external electric field is more pronounced on 
the charge distribution. However, I am not sure how the MD are in 
general affected by such an option.

Any commends and suggestions are appreciated.

Best Regards

Theodoros