GPW calculations with hybrid functionals

[mguidon]

Hi Simone

> Could you please explain to me why the MOLOPT basis sets are very
> expensive when used together with HFX?
> Are they more extended than the corresponding non-molecularly
> optimized basis sets?

Thats the main reason. If you compare for example the most diffuse
exponents for Oxygen in the standard TZVP (0.14) basis and the TZVP-
MOLOPT  (0.04) you already have one order of magnitude difference.
That means that the screening does not as efficiently kick in as one
might wish. Furthermore, the standard basis sets are much less
contracted (i.e. many zeroes for the coefficients).

I am currently working on that issue

Cheers

Manuel