Dear Jit,
Please remember that one of the biggest errors in the application of DFT
is trying to determine intermolecular interactions using traditional DFT
methods.
Dean
On 7/16/12 12:59 PM, "jit mukherjee" <jitiitkgp.gmail.com> wrote:
>Dear sir,
>I have some systems where pi-pi interaction and hydrogen bonding should
>take a vital role in determining the structure and energetics of the
>system. Now, I had a initial 'bad' structure of the system. So, I
>simulated
>it in amber classical force field. After simulation,I looked upon the
>structure and it seems that there is pi-pi stacking interaction(parallel
>in
>some systems and non-parallel) and also hydrogen bonding because the
>distance between the H-acceptor pair meets the criteria of hydrogen
>bonding.
>
>Now, I am trying to optimizing the simulated structure through the QM
>package TURBOMOLE with density functional theory but using a very low
>level
>method and basis set. After optimization, it seems that the pi-pi stacking
>interaction is no more in the structures!
>
>So,can I take the structure after simulation as the 'real' structure for
>the system or should I use high level quantum method to optimize the
>simulated structure. Actually, my systems are too big to avail the
>computational cost for the high level quantum method.
>
>Regards,
>jit
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Received on Mon Jul 16 2012 - 11:30:03 PDT
