Gaussian 09 .out file format specification (and freqchk)

[surfer96313]

Hello,
I was wondering if anyone could tell me where the documentation exists for the output of Gaussian 09 runs. The .out file is plain text and human readable, but I can only decipher parts and units are not always clear. I would have thought the Gaussian website would have an explicit format FAQ or spec, but I cannot find it.

Any help would be appreciated,
Cheers,
--Jim Parker
Physics and Astronomy
University of Texas at San Antonio

 

[alxm]

I've written programs that read Gaussian log files, (which is a major pain, as there are slight changes between every version) and as far as I know, there's no official specification at all. But everything is normally in atomic units. Hartrees/Angstroms, or Hartrees/Bohrs. Formchk files are documented in the programmer's reference book, at least for G03.

Frankly though, the log files are pretty straightforward - if you know what the program is doing. So if it's unclear, you might need to read up on the method(s) you're using. There's an extensive list of references in the manual.

 

[surfer96313]

alxm,
Thanks for the info. I guess I'll have to ask our IT department if they have the copy of the programmer's reference book, since they handled the purchase of the software. Unless you know of another source. The Gaussian website only freely releases the user's guide and IOps manuals as far as I can tell.

There is a one page synopsis of freqchk in the G09 & G03 user's manuals, which gives some detail, but doesn't help the immediate question I have, which is simply -- are the normal modes that are listed in the .out file and freqchk using mass-weighted coordinates or simply cartesian.

I'm going to just run a simple calculation with H2O to find out, which will work. But I was hoping that there was a simple reference manual that would be definitive on what is printed so that I wouldn't have to "rediscover" what each line of output means.

Cheers,
--Jim

 

[alxm]

There is a one page synopsis of freqchk in the G09 & G03 user's manuals, which gives some detail, but doesn't help the immediate question I have, which is simply -- are the normal modes that are listed in the .out file and freqchk using mass-weighted coordinates or simply cartesian.

Cartesian. Although if you've got symmetry it outputs two geometries ('input orientation' and the symmetrizied 'standard orientation') and I can't remember offhand which of those two coordinate systems they're in, although it should be fairly obvious once you visualize the vectors. In formchk files, all coordinates are usually in Bohrs IIRC, although there might be a number that specifies the unit. (again recalling from memory)

 

[surfer96313]

[Solved] Re: Gaussian 09 .out file format specification (and freqchk)

alxm,
Excellent! Thank you.

Cheers,
--Jim