CCL:G: Optimization preserving chiral centers in gaussian09

[John Keller <jwkeller[-]alaska.edu>]

Hi Mohan,

Try optimizing with a molecular mechanics method first, then MOPAC, then your DFT method. MOPAC2012 is free and the multi-core version is extremely fast.

John Keller

On Sat, Aug 1, 2015 at 8:33 AM, Mohan maruthi sena maruthi.sena]_[gmail.com <owner-chemistry**ccl.net> wrote:

Hi all,

           I am trying to optimize a molecule containing 90 atoms and 4 chiral centers in gaussian 09. I have tried with various methods like HF, DFT, MP2 and semi-emperical. I could not optimize the molecule and the error is convergence problem. In semi emperical method, the chiral centers are lost. Could give some suggestions to optimize such structure, preserving chiral centers in gaussian09.

Thanks & Regards,

Mohan