derivation method for second_derivative of XC functionals

[Axel]

On Apr 18, 2:22 pm, Hanning Chen <chenh... at gmail.com> wrote:
> Dear CP2K users,
>
>   I ran a TDDFPT calculation for excitation energies using PBE as my XC
> functionals. I encountered an error "Please provide a derivation method
> 12:50:04 ERRORL2 in pw_poisson_methods:pw_poisson_solve err=-300 12:50:06
> ERRORL2 in xc:xc_calc_2nd_deriv err=-300  condition FAILED". I guess that
> was caused by a missing parameter for the second derivative of the XC terms.
> Please help me to resolve this issue.

a little grepping through the sources reveals that you should have a
look at:
http://cp2k.berlios.de/manual/CP2K_INPUT/FORCE_EVAL/DFT/XC/XC_GRID.html#desc_XC_DERIV

i don't much about TDDFT, but my guess is that there is no analytical
2nd derivative
for the functional that you are using, so you'd have to use a
numerical method.

have you compared your input to existing test cases?

axel.
>
>  Thanks.
>
> Hanning Chen
>
> Department of Chemistry
> Northwestern University
> Evanston, IL 60208