PC GAMESS/Firefly-related discussion club

Alex Granovsky
gran@classic.chem.msu.su

>  But i have a question about XC functionals, why always pure functionals are much more difficult to converge than hybrid functionals?

It's quite a typical situation, however for many systems,
pure functionals actually converges better.

The "exact" HF exchange has some unique properties,
which seriously distinguish it from GGA-type exchange.
This results in different convergence behavior of
pure HF, pure DFT, and hybrid functionals.