Geometry Optimization using constrained DFT or CDFT-CI?

The question and some valuable suggestions have been raised in an earlier post.

Earlier post
Geometry optimization with constrained DFT - #13 by jherbert

But I’m using Q-CHEM 5.4.1 and I haven’t finished any single CDFT-optimization(or CDFT-CI optimization) task successfully(optimization under normal DFT seems okay though), including example offered in the post above. Strange energy hoppings still exist in my case and increasing OPT_MAX_CYCLE seems to help little. My input/output files for the job are in this page.

Hello Jingdan,

We are still trying to figure out the source of problem. In the meantime, you can add BECKE_SHIFT = UNSHIFTED to get it converged.


Glad to see that BECKE_SHIFT=UNSHIFTED works. Looking forward to your further discovery. Thanks for kind response.

I was going to reply with same comment. Converges in 13 steps with the latest version, 6.0.1