What do you mean by "For charges, if I use bcc at first, but the density
would not converge."
It does not converge or it does to the wrong value?
Also, it is not only about charges, the vdw parameters also metter for
the density.
On 11/13/11 3:52 PM, Dr. Vitaly V. Chaban wrote:
> On Sat, Nov 12, 2011 at 1:22 PM, Ismail, Mohd F.<farid.ou.edu> wrote:
>> I am trying to simulate ions in bulk organic solvent. I use gaff for internal parameters. For charges, if I use bcc at first, but the density would not converge. When I use RED, the density is still about 3% higher.
>>
>> Will it be alright if I use higher method or basis set to calculate the charges? I saw some documentation that gaff and amber use HF with 6-31g* for the parameters and charges.
>>
>> I also check the trajectory, but there seems to be no 'stupid' conformation.
>
> The charges are always very sensitive to the ab initio method applied.
> Try MP2 instead, for example. BTW, 3% higher density is not so much
> terrible for most tasks.
>
>
> Dr. Vitaly V. Chaban, 430 Hutchison Hall, Chem. Dept.
> Univ. Rochester, Rochester, New York 14627-0216
> THE UNITED STATES OF AMERICA
>
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--
Dr. Adrian E. Roitberg
Professor
Quantum Theory Project, Department of Chemistry
University of Florida
roitberg.ufl.edu
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Received on Sun Nov 13 2011 - 13:00:05 PST
