TURBOMOLE Modules > Ricc2
CC2 with COSMO for excited states
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user20212707:
Dear Turbomole forum,
I am currently trying to calculate the excited state energy for small superoxides at the approximate CC2 level of theory including solvation effects via COSMO in the ricc2-module. These systems are open shell systems, containing symmetry elements of the C2v-group. I am simply considering an array of prepared geometries, so the calculations are mostly single-point calculations without a previous optimization of the molecule to the electronic ground state (or any excited state).
Without invocing COSMO (via cosmoprep) these calculations converge readily and I obtain all required excitation energies and properties.
When I include COSMO however the computation always fails in the optimization of the ground state cluster amplitudes.
I oriented myself on the examples in the manual for the calculation of the ricc2-energies:
--- Code: ---$ricc2
cc2
$excitations
irrep=a1 nexc=3 npre=3 nstart=3
exprop states=all relaxed operators=overlap,diplen,angmom,soc
$response
fop relaxed
--- End code ---
and for the COSMO-part:
--- Code: ---$cosmo
epsilon=4.33
rsolv=1.30
refind=1.3524
cosmorel state=(a1 2)
$cosmo_atoms
...
$cosmo_correlated
--- End code ---
Notably, whichever cosmorel state I use, the error is always the same.
A dscf calculation of the molecule runs smoothly, but the ricc2 calculation after that one gives the following error (given below is the end of the file):
--- Code: --- **************************************************************************
* *
* OPTIMIZATION OF THE GROUND STATE CLUSTER AMPLITUDES *
* *
**************************************************************************
Reaction field calculation using the COSMO solvation model
Reaction field scheme : post-SCF
Reaction field density : full unrelaxed
epsilon : 4.330
f(epsilon) : 0.689441
start CC2 from scratch because restart not enabled
Iter. MP2 energy Norm(Omega) Norm(Ombar) Norm(t1) Norm(t2) cpu wall
................................................................................
========================
internal module stack:
------------------------
ricc2
cc2_solve_t0
cc_lhtr
========================
unfinished (do_t1res and open-shell)
ricc2 ended abnormally
--- End code ---
I am not sure how to fix, or even interpret this error as something other than CC2 is having internal problems. At first I thought it might have something to do with the OMP_stacksize, but the latter is unlimited on the server I am using. I think with generous $maxcor settings (> 5100 MiB per_core) there should also not be a lack of memory. In addition, decreasing the basis from cc-pVQZ to cc-pVTZ or even cc-pVDZ did not avoid the error.
I am very grateful for your suggestions and help. If additional input/output is required, I will hurry to deliver it.
Thanks,
Dennis
christof.haettig:
COSMO-CC2 is not implemented with symmetry, also the post-SCF reaction field coupling scheme doesn't work together with the cosmorel option in the COSMO input. Also, excited-state properties are not yet implemented for COSMO-CC2.
shafikoff:
Dear Christof,
Are there any plans to implement CC2-COSMO for excited states in Turbomole in near future?
Thanks,
Marsel
christof.haettig:
COSMO-CC2 is available for excitation energies (not gradients) in ricc2 since some years within the post-SCF coupling scheme. The problem of your calculation was that your input asks for the PTED coupling scheme which is only implemented for ADC(2).
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