Multiwfn forum

gibacic

Member

Registered: 2019-11-19

Posts: 3

CDA and coordinates from Gaussian

Hi Tian,

I've been trying to perform CDA (and ECDA) on a transition metal complex of mine, but I keep getting an error about the coordinates being different between my fragments.

I followed the instructions in the manual and added "nosymm pop=full" to my fragments' route section and "nosymm pop=full IOp(3/33=1)" to the complex SP calculation.

Looking at the formatted checkpoints with Avogadro, it seems that somewhere (either in Gaussian or when made by formchk) the indices of the nuclei were rearranged (and moved by ~0.0001 A).

How do I prevent or fix this?

Thanks in advance for your help!
g

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,773

Website

Re: CDA and coordinates from Gaussian

Dear gibacic,

Please directly use .fchk file as input file of the CDA module, because in this case you do not need to specify "pop=full IOp(3/33=1)", also because the recording precision of the data in .fchk file is higher than output file.

After complex calculation, simply use gview to open the Gaussian output file or corresponding .fchk file, save the coordinate as .gjf file, and then split it as two monomer input files, then add "nosymm" keyword. The coordinate in the resulting monomer .fchk files should be exactly identical to the complex .fchk file.

PS: I am not an Avogadro user. If you do not have gview in hand, you can also use Multiwfn to load the complex .fchk file, then enter main function 100, use its subfunction 2 to export complex coordinate as .gjf file.

Tian