How to get oscillator strength EOM-CCSD


I want to compute excitation energies within EOM-CCSD method with the following input :

METHOD eom-ccsd
ee_triplets 5
ee_singlets 5
calc_soc 1
solvent_method PCM
MEM_TOTAL 100000


theory                  CPCM

Dielectric              2.38
OpticalDielectric       1.9599999999999997

0 1

Which after the Davidson procedure has converged returns for the first singlet excited state :

 Excited state properties for  EOMEE-CCSD transition 1/A
 Dipole moment (a.u.): 0.152199 (X -0.073891, Y -0.115661, Z 0.065782)
 R-squared (a.u.): 1738.140327 (XX 855.376183, YY 825.213699, ZZ 57.550445)
 Gauge origin (a.u.): (0.000000, 0.000000, 0.000000)
 Angular momentum (a.u.) against gauge origin:
 (X 0.020760i, Y -0.032854i, Z -0.009493i)
 Traces of the OPDMs: Tr(AA) 44.000000, Tr(BB) 44.000000
 <S^2> = -0.000000

And thus my questions are where do I get the oscillator strength associated to this transition ? And what does OPDMs mean ?

Best regards,


OPDM = one-particle density matrix.

The oscillator strengths should appear farther down in the output, e.g., using your input file for H2O molecule:

 EOMEE-CCSD calculation:   CPU 5.06 s  wall 3.24 s

 Start computing the transition properties

 The new SOC module will be executed
 Authors: Pavel Pokhilko and Evgeny Epifanovsky
 SOC 1e and mf integrals are evaluating by libqints...
 State A: ccsd: 0/A
 State B: eomee_ccsd/rhfref/singlets: 1/A
 Energy GAP = 0.314615 a.u. = 8.561106 eV
 Transition dipole moment (a.u.):
   A->B: 0.369590 (X 0.000000, Y -0.369590, Z 0.000000)
   B->A: 0.376400 (X 0.000000, Y -0.376400, Z 0.000000)
 Oscillator strength (a.u.): 0.029178
 Transition angular momentum against gauge origin (a.u.):
   A->B:  (X -0.115529i, Y 0.000000i, Z 0.149221i)
   B->A:  (X 0.118861i, Y 0.000000i, Z -0.153525i)
 Norm of one-particle transition density matrix:
   A->B: 0.957596;   B->A: 0.970619
   ||gamma^AB||*||gamma^BA||: 0.929461

To compute transition properties (such as oscillator strength), you need to add this to the input: CC_TRANS_PROP = 1

Hello, I want to calculate the resonant auger decay using the EOM-CCSD. The output calculated according to the cvs-ee-states and ip-states instructions used in the Q-chem manual belongs only to the resonant participator decay. How to configure it to calculate the resonance spectator decay? thanks.

In the case of resonant Auger decay, we distinguish between participator and spectator/observer decay. The decay channels for participator decay are 1h states and decay channels for spectator decay are 2h1p states. Both 1h and 2h1p states can be computed by EOM-IP-CCSD, however, the energies of the latter states will be overestimated. The two types of states can be distinguished by analyzing EOM-IP amplitudes: the states with R1^2 close to 1 correspond to participator decay whereas those with R2^2 close to 1 correspond to spectator decay.

Here’s a sample of the rem section of the input for the benzene molecule (for the opitmized structure see J. Chem. Phys., 158, 064109, (2023)):

jobtype = sp
method = eom-ccsd
ip_states [4,0,0,0,0,0,0,0]
cvs_ee_states [0,0,0,0,0,0,1,0]
basis = gen
mem_total = 100000

In the output you will find the first three EOM-IP states with R1^2 close to 1 (participator decay) and the fourth EOM-IP state with R2^2 is close to 1 (spectator/observer decay)

Ok, thank you very much for your answer!