CCL:G: Gaussian 09 and 16 compared for mundane calculations

[Uche Anene <uche|*|uconn.edu>]

Andrew,

There’s no major difference between G09 and G16 that you can’t adjust to make them the same. For example, the default settings for convergence and SCF are higher in G16 but you can change them to be consistent with G09.

Here’s a list of the changes

https://gaussian.com/gdiffs/

Happy computing,

Uche 

Uchenna A. Anene

Ph.D. Candidate, Chemical Engineering  

University of Connecticut

Innovation Partnership Building 

159 Discovery Drive, Unit# 5279

Storrs, CT 06269

Email: uche=uconn.edu

Group Website: https://alpay.ims.uconn.edu/uche-anene/#

LinkedIn: www.linkedin.com/in/uche-anene

ResearchGate: https://www.researchgate.net/profile/Uchenna_Anene 

Twitter: https://twitter.com/ThatsSoUche

On Mar 3, 2022, at 5:30 PM, Andrew DeYoung andrewdaviddeyoung##gmail.com <owner-chemistry�.net> wrote:

*Message sent from a system outside of UConn.*

Hi,

My institution has both Gaussian 09 and Gaussian 16, and I'm trying to decide which to use for my new project.  (My background is in applications of MD simulations, and I'm quite new to quantum chemistry.)  One reason to use 16 is that, well, it's the latest version.  One reason to use 09 is for consistency; it's been used in our group a lot in the past.

My colleague said he observed some different results > from 09 and 16, though he didn't remember how large the differences were.  

I will likely do some of my own comparisons, but I am curious, does anyone have experience with this?

The calculations I will be doing for my project are pretty mundane: using RHF to optimize geometry, and using MP2 to calculate the energy and extract charges with CHelpG.  The basis sets I will use are fairly pedestrian -- 6-31G(d), cc-pVTZ, etc -- nothing particularly exotic.  

From looking at this page ( https://gaussian.com/gdiffs/ ), it looks like Gaussian 16 mainly added new methods and basis sets.  I can imagine that algorithm improvements/tweaks (faster, more effective parallelization, etc) could give rise to some numerical differences, but I would not expect these differences to be terribly significant for most properties.  Is this your experience?

Thanks for your time,

Andrew

Andrew DeYoung, PhD

Department of Chemistry

Carnegie Mellon University