AMBER Archive (2009)

Subject: [AMBER] PES QM and MM

From: s. Bill (s_bill36_at_yahoo.co.uk)
Date: Thu Sep 17 2009 - 05:53:46 CDT

Dear AMBER
Could you share me with your experience, please?
I am working on optimizing VDW parameters of one metal ion, my supervisor suggested to draw ab initio potential energy surface for one coordinate (using scan keyword in Gaussian, Hard Scan option) and to draw the potential surface for the same coordinate using AMBER Force Field. We found that the well-depth in ab initio is around 100 kcal/mol and is around 225 kcal/mol, i.e. it is greater in case of MM potentail energy surface. So, we decided to change epislon VDW parameters of the metal ion, but We surprised when we found the well-depth decreased with increasing the epislon value. Is it right? we don't believe that!!!
So, why is it happened?
Thanks in advance;
S, Bill

      
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