## Firefly and PC GAMESS-related discussion club

Learn how to ask questions correctly

** Re^2: Puzzled results from MCSCF geometry optimization **
Panwang Zhou

pwzhou@gmail.com

Dear Pedro Silva,Thanks for your comments.

Yes, I din not request symmetry in my calculations. However, I also did not request symmetry in my DFT calculations with G16, the obtained geometry keeps the C2v symmetry. Acutally, in my previous calculations, I have not request any symmetry constraint and I had never enountered this problem. Thus, in my opinion, even if I did not request any symmetry, the optimized geometry should keep its symmetry, is it right? Thanks.

Best Regards!

On Mon Dec 4 '17 4:47pm, Pedro Silva wrote

------------------------------------------

>>Dear Panwang Zhou,

>Your output states that you did not request C2v symmetry in the optimization algorithm. In your DATA deck, you should replace the C1 line by "Cnv 2" , followed by a blank line and by your geometry, suitably rotated/translated/etc to comply with the internal master frame detection conventions:

>By default, the 'master frame' assumes that

>1. z is the principal rotation axis (if any),

>2. x is a perpendicular two-fold axis (if any),

>3. xz is the sigma-v plane (if any), and

>4. xy is the sigma-h plane (if any).

>Use the lowest number rule that applies to your molecule.

>

>

>Some programs (eg. ChemCraft) allow you to select the symmetry and automatically generated properly-formatted $DATA groups to ensure that your computation does not face trouble because of deficient adherence to those conventions.

>

Tue Dec 5 '17 5:27am

This message read **303** times