Hello Lamthaka Willingson

It seems there is a typo regarding the input of the basis set, or you are trying to use the GENECP keyword. It would be helpful if you could provide more information regarding the input.

You may find these links helpful for running the Gaussian program.

Tutorial: https://barrett-group.mcgill.ca/tutorials/Gaussian%20tutorial.pdf

YT channel: https://www.youtube.com/@IaNiusha

Gaussian YT channel: https://www.youtube.com/@GaussianInc

I hope this helps!

Thanks, Dilawar Singh Sisodiya

I'm sending you my Gaussian input file

Hey Lamthaka Willingson: Could you please send your input file or output?

That way it may be more helpful to identify the error message better and then resolve it. This link may also help you regarding gen keyword:

https://docs.alliancecan.ca/wiki/Gaussian_error_messages

I also agree with Dilawar Singh Sisodiya

Mohammadreza Sharghi , i'm sending you the output file

Hello Lamthaka Willingson

You are using a custom basis for input, and there is a format to add them.

You may find this blog helpful.

Blog Link: https://joaquinbarroso.com/2011/11/02/gen-keyword-gaussian/

You want to use a general basis set and a pseudo potential, but neither of them are specified in your input file.

To do that, after the cartesian coordinates + a blank line you should give the basis set and pseudopotential you want to use.

I copy and example:

Fe 0

SDD

F 1 1.0

2.462 1.0

****

I 0

SDD

D 1 1.00

0.289

****

C H O 0

6-31G(d,p)

****

Fe I

SDD

Lamthaka Willingson

It looks like there's a syntax error in your Gaussian input file related to the basis set specification. Here’s a step-by-step guide to help you troubleshoot and fix this issue:

1. Check the Input File Structure: Ensure your input file follows the correct Gaussian input file format. A basic structure looks like this:

perlCopy code%NProcShared=4 %Mem=8GB #P B3LYP/6-31G(d) Opt Title Section: Water-Silver Complex Optimization 0 1 O 0.00000 0.00000 0.00000 H 0.75700 0.58600 0.00000 H -0.75700 0.58600 0.00000 Ag 2.00000 0.00000 0.00000

Header Section: Specifies computational resources and method. Title Section: Brief description of the calculation. Charge and Multiplicity: Followed by the molecular coordinates. Geometry Section: Atom types and coordinates.

2. Verify Basis Set Specification:The error message suggests a problem with the basis set specification. Ensure you have specified a valid basis set correctly. For example:

scssCopy code#P B3LYP/6-31G(d) Opt

Alternatively, if using a custom basis set, ensure the basis set block is correctly formatted and complete.

3. Common Issues to Look For:Missing or extra spaces. Incorrect line breaks. Incorrect atom labels or coordinates. Ensure no additional characters or missing values in the coordinates section.

4. Example Input File for Water-Silver Complex:Here’s an example input file for a water-silver complex: perlCopy code%NProcShared=4 %Mem=8GB #P B3LYP/6-31G(d) Opt Water-Silver Complex Optimization 0 1 O 0.00000 0.00000 0.00000 H 0.75700 0.58600 0.00000 H -0.75700 0.58600 0.00000 Ag 2.00000 0.00000 0.00000

5. Detailed Error Check:If the error persists, please share the exact content of your input file. This will help to identify the specific syntax issue.

By following these steps and ensuring the correct format and basis set specification, you should be able to resolve the syntax error and successfully run your DFT calculations in Gaussian.

Feel free to share more details if you need further assistance.

Best regards,

Sandeep Jaiswal