Tinker has such an option.

Hi Ramsay,

You can use Gaussian. This is a commercial software.

Otherwise you might want to apply for an academic license to run the OpenEye package.

Thanks

Fidele

Hi Ramsay,

For the generation of conformers, you can use Accelrys Discovery Studio, Schrodinger and other paid softwares.  Among the free wares Openbabel, FROG etc can be used

I just would like to support Fidele that concerning conformers, particularly if they differ only by rotational angles around single or partially double bonds, strict quantum mechanical ab initio methods are requested, and even possible that beyond Hartree-Fock perturbational procedures are needed such as MP or Coupled Cluster.

Dear Andras,

Certainly, you are correct. When Running the calculations, choice of method versus CPU time are factors to take into consideration Ramsay. 

Dear Colleagues

Many thanks for your help.

Hi Ramsay,

      there are several open source program for conformer generation: balloon, MulticonfDock, Rdkit ... However, keep in mind that, if your system has a fairly larggg number of rotatable bons, you nay end up with several hundreds of conformers. Then, an efficient clustering methods is required to select the most representative. I would suggest to refer to the very good paper by Ebejer (Ebejer, Jean-Paul, Morris, Garrett M and Deane, Charlotte M. "Freely available conformer generation methods: how good are they?." Journal of chemical information and modeling 52, no. 5 (2012): 1146—58). Hope it may help.

Hi Ramsay,

I personally use the commercial program PCMODEL from Serena Software. Its option GMMX generates and records the hundreds of different conformers. Of course, after the selection it is necessary additionally to optimize their. Then I apply Gaussian,

I hope this may help you,

Ryszard

Hi Ryszard

THanks for the help. I will try to have this software. if i have problems, i will contact you again.

Thanks