Error in EOM-CC calculation

Dear friends,

I ran to some errors while trying EOM-CC calculations.

  1. for error: ** Lambda not converged to 1.0e-07 **
    what input should I include to make it working?

  2. for error: PSIO_ERROR: Can’t find TOC Entry EOM CC2 Energy for root 1 4
    what should I do with it? I checked the output and it seems all the roots I needed were converged, including root 1 4.

  3. my iput is something like this:

set {
basis aug-cc-pVDZ
freeze_core true
roots_per_irrep [5, 5]

property(‘eom-cc2’, properties=[‘oscillator_strength’])

My molecule is quite small (8 atoms). If I need a lot of roots (around 200 roots, which can be done easily with TDDFT), is it feasible with EOM-CC2? if yes, what input are needed to control the convergence?

Thank you very much!

Best regards,

The default convergence of the CCLAMBDA code for transition properties, such as oscillator strengths is too tight, and I need to adjust it. In the meantime, you should be able to get a significant number of states – but probably not 200 – by adding the following to your input file:

set cclambda {
  r_convergence 1e-3
set cceom {
  r_convergence 1e-3
  e_convergence 1e-5


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