Help: EOM-CC calculation

1

Dear All,
I was trying to carry out an EOM-CC calculation. If I set roots_per_irrep for 15, everything is fine. While I got error when I increased the number to 25. Which keyword should I adjust to make it working?

The error is: RuntimeError: cclambda: error
** Lambda not converged to 1.0e-07 **

My input is:

set {
basis aug-cc-pVDZ
freeze_core true
roots_per_irrep [25,25]
}

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

Thank you very much!
Best regards,

Michael Morgan

2

I haven’t seen the output, but I’d bet that the calculation is simply failing because the default convergence criteria on the lambda equations is tighter than necessary for computing oscillator strengths. Try adding the following above the property() directive:

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

-TDC

3

Thank you! Adding “set cclambda r_convergence 1e-3” along solve the problem. Cheers!
Michael