Two-photon absorption using RI-CC2

[mehboob]

Respected users,

I'm trying to prepare an input file for a two-photon absorption calculation at the RI-CC2 level of theory using "define". But I'm lost actually. As mentioned in the manual, the two-photon calculations can be run using escf but I'm unable to make my way to this part using define. Actually I used "ex" but it leads to rpas, ciss, urpa, ucis methods but there is no option for RI-CC2. Any help would be highly appreciated.

Best regards,
Mehboob

[Arnim]

Hello Mehboob,

the 'ex' menu sets the keywords for TDDFT.

The settings for twophoton computation with ricc2 are not yet (status version 7.5) available in define.
You have to put the keywords manually in the control file.
E.g.:
 
$ricc2
  cc2
$excitations
  irrep=a nexc=1
  twophoton states=all operators=(diplen,diplen) freq=0.1d0
$laplace
  conv=6

Cheers,
Arnim

[mehboob]

Thank you Arnim.