CCSD calculation with energy('ccsd')

I was runed Psi4 code through Chemcompute to get MO energy to assign HOMO LUMO energy
Im confused If i get HF. SCF or CCSD corresponding energy ?
the input code was:

#! filename=unnamed

# Psi4 Calculation input file

memory 32000 mb

molecule m {
C 0.954591949995 -0.682318626527 0.000698231345
C 0.993113878088 0.734934436760 0.011510219876
C -0.222152441354 1.444423638517 0.010080218944
C -1.405896732742 0.734445456003 -0.002767419914
C -1.424485721686 -0.681521226141 -0.013818952372
C -0.243481380060 -1.402616172031 -0.011958326123
N 2.262218754757 -1.125762450644 0.005328841940
C 3.114536641280 -0.036138695442 0.018526537270
C 2.377401343747 1.117367175567 0.022809958592
O -2.663320224474 1.314064505216 -0.004828582125
O -2.620055229165 -1.343863878096 -0.026980990177
H -0.233947570964 2.530269733861 0.019059465204
H -0.279396865092 -2.485294775496 -0.020685434005
H 2.551507652313 -2.088872181104 -0.000904505855
H 4.183721402179 -0.176697123159 0.023918462764
H 2.775902582574 2.119766115988 0.032873085338
H -2.589120681415 2.272843078508 -0.011188173641
H -3.327186996390 -0.685783167156 -0.029969818244
}

set {
basis aug-cc-pvdz
reference RHF
}

set ccenergy print 3

E, wfn = energy(‘ccsd’, return_wfn=True)
wfn.write_molden(‘Psi4.molden’)

print_variables()
print(f"Ahmed printed Energy: {E} Hartree")
print(f"Ahmed printed wfn obj: {wfn} ")

with open(‘Psi4.molden’, ‘r’) as file:
molden_contents = file.read()
print(“Molden File Contents:”)
print(molden_contents)

Output :slight_smile:

      Psi4: An Open-Source Ab Initio Electronic Structure Package
                           Psi4 1.5 release

                     Git: Rev {HEAD} e9f4d6d 


D. G. A. Smith, L. A. Burns, A. C. Simmonett, R. M. Parrish,
M. C. Schieber, R. Galvelis, P. Kraus, H. Kruse, R. Di Remigio,
A. Alenaizan, A. M. James, S. Lehtola, J. P. Misiewicz, M. Scheurer,
R. A. Shaw, J. B. Schriber, Y. Xie, Z. L. Glick, D. A. Sirianni,
J. S. O'Brien, J. M. Waldrop, A. Kumar, E. G. Hohenstein,
B. P. Pritchard, B. R. Brooks, H. F. Schaefer III, A. Yu. Sokolov,
K. Patkowski, A. E. DePrince III, U. Bozkaya, R. A. King,
F. A. Evangelista, J. M. Turney, T. D. Crawford, C. D. Sherrill,
J. Chem. Phys. 152(18) 184108 (2020). https://doi.org/10.1063/5.0006002

                        Additional Code Authors
E. T. Seidl, C. L. Janssen, E. F. Valeev, M. L. Leininger,
J. F. Gonthier, R. M. Richard, H. R. McAlexander, M. Saitow, X. Wang,
P. Verma, M. H. Lechner, and A. Jiang

         Previous Authors, Complete List of Code Contributors,
                   and Citations for Specific Modules
https://github.com/psi4/psi4/blob/master/codemeta.json
https://github.com/psi4/psi4/graphs/contributors
http://psicode.org/psi4manual/master/introduction.html#citing-psifour

-----------------------------------------------------------------------


Psi4 started on: Saturday, 15 March 2025 01:41PM

Process ID: 13
Host:       chemcompute-node-0.novalocal
PSIDATADIR: /usr/local/share/psi4
Memory:     500.0 MiB
Threads:    8

==> Input File <==

---

#! filename=unnamed

# Psi4 Calculation input file

memory 32000 mb

molecule m {
C 0.954591949995 -0.682318626527 0.000698231345
C 0.993113878088 0.734934436760 0.011510219876
C -0.222152441354 1.444423638517 0.010080218944
C -1.405896732742 0.734445456003 -0.002767419914
C -1.424485721686 -0.681521226141 -0.013818952372
C -0.243481380060 -1.402616172031 -0.011958326123
N 2.262218754757 -1.125762450644 0.005328841940
C 3.114536641280 -0.036138695442 0.018526537270
C 2.377401343747 1.117367175567 0.022809958592
O -2.663320224474 1.314064505216 -0.004828582125
O -2.620055229165 -1.343863878096 -0.026980990177
H -0.233947570964 2.530269733861 0.019059465204
H -0.279396865092 -2.485294775496 -0.020685434005
H 2.551507652313 -2.088872181104 -0.000904505855
H 4.183721402179 -0.176697123159 0.023918462764
H 2.775902582574 2.119766115988 0.032873085338
H -2.589120681415 2.272843078508 -0.011188173641
H -3.327186996390 -0.685783167156 -0.029969818244
}

set {
basis aug-cc-pvdz
reference RHF
}

set ccenergy print 3

E, wfn = energy(‘ccsd’, return_wfn=True)
wfn.write_molden(‘Psi4.molden’)

print_variables()
print(f"Ahmed printed Energy: {E} Hartree")
print(f"Ahmed printed wfn obj: {wfn} ")

## with open(‘Psi4.molden’, ‘r’) as file:
molden_contents = file.read()
print(“Molden File Contents:”)
print(molden_contents)

Memory set to 29.802 GiB by Python driver.

Scratch directory: /scratch/

*** tstart() called on chemcompute-node-0.novalocal
*** at Sat Mar 15 13:41:37 2025

=> Loading Basis Set <=

Name: AUG-CC-PVDZ
Role: ORBITAL
Keyword: BASIS
atoms 1-6, 8-9 entry C          line   182 file /usr/local/share/psi4/basis/aug-cc-pvdz.gbs 
atoms 7        entry N          line   218 file /usr/local/share/psi4/basis/aug-cc-pvdz.gbs 
atoms 10-11    entry O          line   254 file /usr/local/share/psi4/basis/aug-cc-pvdz.gbs 
atoms 12-18    entry H          line    40 file /usr/local/share/psi4/basis/aug-cc-pvdz.gbs 


     ---------------------------------------------------------
                               SCF
           by Justin Turney, Rob Parrish, Andy Simmonett
                      and Daniel G. A. Smith
                          RHF Reference
                    8 Threads,  30517 MiB Core
     ---------------------------------------------------------

==> Geometry <==

Molecular point group: c1
Full point group: C1

Geometry (in Angstrom), charge = 0, multiplicity = 1:

   Center              X                  Y                   Z               Mass       
------------   -----------------  -----------------  -----------------  -----------------
     C            0.954591949995    -0.682318626527     0.000698231345    12.000000000000
     C            0.993113878088     0.734934436760     0.011510219876    12.000000000000
     C           -0.222152441354     1.444423638517     0.010080218944    12.000000000000
     C           -1.405896732742     0.734445456003    -0.002767419914    12.000000000000
     C           -1.424485721686    -0.681521226141    -0.013818952372    12.000000000000
     C           -0.243481380060    -1.402616172031    -0.011958326123    12.000000000000
     N            2.262218754757    -1.125762450644     0.005328841940    14.003074004430
     C            3.114536641280    -0.036138695442     0.018526537270    12.000000000000
     C            2.377401343747     1.117367175567     0.022809958592    12.000000000000
     O           -2.663320224474     1.314064505216    -0.004828582125    15.994914619570
     O           -2.620055229165    -1.343863878096    -0.026980990177    15.994914619570
     H           -0.233947570964     2.530269733861     0.019059465204     1.007825032230
     H           -0.279396865092    -2.485294775496    -0.020685434005     1.007825032230
     H            2.551507652313    -2.088872181104    -0.000904505855     1.007825032230
     H            4.183721402179    -0.176697123159     0.023918462764     1.007825032230
     H            2.775902582574     2.119766115988     0.032873085338     1.007825032230
     H           -2.589120681415     2.272843078508    -0.011188173641     1.007825032230
     H           -3.327186996390    -0.685783167156    -0.029969818244     1.007825032230

Running in c1 symmetry.

Rotational constants: A = 0.08911 B = 0.02803 C = 0.02132 [cm^-1]
Rotational constants: A = 2671.43577 B = 840.22126 C = 639.18498 [MHz]
Nuclear repulsion = 577.909070003520355

Charge = 0
Multiplicity = 1
Electrons = 78
Nalpha = 39
Nbeta = 39

==> Algorithm <==

SCF Algorithm Type is PK.
DIIS enabled.
MOM disabled.
Fractional occupation disabled.
Guess Type is SAD.
Energy threshold = 1.00e-08
Density threshold = 1.00e-08
Integral threshold = 1.00e-12

==> Primary Basis <==

Basis Set: AUG-CC-PVDZ
Blend: AUG-CC-PVDZ
Number of shells: 134
Number of basis functions: 316
Number of Cartesian functions: 338
Spherical Harmonics?: true
Max angular momentum: 2

==> Integral Setup <==

Using in-core PK algorithm.
Calculation information:
Number of atoms: 18
Number of AO shells: 134
Number of primitives: 324
Number of atomic orbitals: 338
Number of basis functions: 316

  Integral cutoff                 1.00e-12
  Number of threads:                 8

Performing in-core PK
Using 2508657482 doubles for integral storage.
We computed 40557650 shell quartets total.
Whereas there are 40910535 unique shell quartets.

==> DiskJK: Disk-Based J/K Matrices <==

J tasked:                  Yes
K tasked:                  Yes
wK tasked:                  No
Memory [MiB]:            22888
Schwarz Cutoff:          1E-12

OpenMP threads:              8

Minimum eigenvalue in the overlap matrix is 1.2740134189E-06.
Reciprocal condition number of the overlap matrix is 8.1206721068E-08.
Using symmetric orthogonalization.

==> Pre-Iterations <==

SCF Guess: Superposition of Atomic Densities via on-the-fly atomic UHF (no occupation information).

---

Irrep   Nso     Nmo    

---

 A        316     316 

---

Total     316     316

---

==> Iterations <==

                    Total Energy        Delta E     RMS |[F,P]|

@RHF iter SAD: -511.04690308021509 -5.11047e+02 0.00000e+00
@RHF iter 1: -510.95701739613901 8.98857e-02 2.25177e-03 DIIS
@RHF iter 2: -511.19480049476891 -2.37783e-01 1.08935e-03 DIIS
@RHF iter 3: -511.25008486977174 -5.52844e-02 2.49428e-04 DIIS
@RHF iter 4: -511.25394694388882 -3.86207e-03 1.07007e-04 DIIS
@RHF iter 5: -511.25463390630671 -6.86962e-04 1.79043e-05 DIIS
@RHF iter 6: -511.25467047148362 -3.65652e-05 9.14189e-06 DIIS
@RHF iter 7: -511.25467983573463 -9.36425e-06 3.06465e-06 DIIS
@RHF iter 8: -511.25468201003468 -2.17430e-06 1.15255e-06 DIIS
@RHF iter 9: -511.25468235177340 -3.41739e-07 5.65464e-07 DIIS
@RHF iter 10: -511.25468242899433 -7.72209e-08 2.66086e-07 DIIS
@RHF iter 11: -511.25468245124506 -2.22507e-08 9.48651e-08 DIIS
@RHF iter 12: -511.25468245327369 -2.02863e-09 4.27572e-08 DIIS
@RHF iter 13: -511.25468245355967 -2.85979e-10 1.50285e-08 DIIS
@RHF iter 14: -511.25468245359821 -3.85398e-11 5.32748e-09 DIIS
Energy and wave function converged.

==> Post-Iterations <==

Orbital Energies [Eh]
---------------------

Doubly Occupied:                                                      

   1A    -20.605479     2A    -20.588593     3A    -15.609655  
   4A    -11.301729     5A    -11.299160     6A    -11.275084  
   7A    -11.272323     8A    -11.244609     9A    -11.236277  
  10A    -11.232534    11A    -11.224023    12A     -1.419913  
  13A     -1.386512    14A     -1.296277    15A     -1.131057  
  16A     -1.058381    17A     -1.000881    18A     -0.975902  
  19A     -0.869897    20A     -0.815683    21A     -0.793938  
  22A     -0.766780    23A     -0.721444    24A     -0.688997  
  25A     -0.672231    26A     -0.613036    27A     -0.608414  
  28A     -0.607710    29A     -0.590248    30A     -0.580942  
  31A     -0.575313    32A     -0.552985    33A     -0.552213  
  34A     -0.539227    35A     -0.493763    36A     -0.440172  
  37A     -0.381720    38A     -0.294892    39A     -0.272034  

Virtual:                                                              

  40A      0.031104    41A      0.032129    42A      0.041424  
  43A      0.052070    44A      0.055489    45A      0.075164  
  46A      0.078074    47A      0.088106    48A      0.106916  
  49A      0.115325    50A      0.123188    51A      0.124023  
  52A      0.128894    53A      0.133120    54A      0.140887  
  55A      0.141772    56A      0.143692    57A      0.144393  
  58A      0.149342    59A      0.154700    60A      0.163092  
  61A      0.167591    62A      0.170599    63A      0.174196  
  64A      0.181647    65A      0.189380    66A      0.193595  
  67A      0.195905    68A      0.204515    69A      0.206840  
  70A      0.211338    71A      0.226129    72A      0.226287  
  73A      0.240584    74A      0.245210    75A      0.245592  
  76A      0.264977    77A      0.268060    78A      0.283788  
  79A      0.286517    80A      0.288159    81A      0.290042  
  82A      0.300739    83A      0.301984    84A      0.312210  
  85A      0.319069    86A      0.328672    87A      0.334856  
  88A      0.335786    89A      0.352864    90A      0.359876  
  91A      0.365013    92A      0.374135    93A      0.376209  
  94A      0.379748    95A      0.383027    96A      0.386227  
  97A      0.402425    98A      0.411278    99A      0.419168  
 100A      0.429243   101A      0.429933   102A      0.435515  
 103A      0.447969   104A      0.453877   105A      0.455283  
 106A      0.473233   107A      0.474452   108A      0.488317  
 109A      0.492645   110A      0.499157   111A      0.506286  
 112A      0.509795   113A      0.524451   114A      0.531139  
 115A      0.541041   116A      0.551812   117A      0.554722  
 118A      0.586587   119A      0.590460   120A      0.591514  
 121A      0.601473   122A      0.603799   123A      0.609465  
 124A      0.612047   125A      0.624428   126A      0.631781  
 127A      0.641871   128A      0.656455   129A      0.666507  
 130A      0.673240   131A      0.677628   132A      0.681217  
 133A      0.687952   134A      0.690122   135A      0.693638  
 136A      0.697839   137A      0.710668   138A      0.714035  
 139A      0.716617   140A      0.729779   141A      0.736358  
 142A      0.743148   143A      0.750064   144A      0.762521  
 145A      0.774151   146A      0.777745   147A      0.793516  
 148A      0.803806   149A      0.814953   150A      0.820569  
 151A      0.846659   152A      0.856389   153A      0.859724  
 154A      0.871457   155A      0.882386   156A      0.894994  
 157A      0.897853   158A      0.901613   159A      0.906530  
 160A      0.936568   161A      0.946073   162A      0.954773  
 163A      0.956356   164A      0.963839   165A      0.974227  
 166A      0.998944   167A      1.002874   168A      1.020131  
 169A      1.021138   170A      1.033097   171A      1.037350  
 172A      1.044347   173A      1.058046   174A      1.084784  
 175A      1.090880   176A      1.107154   177A      1.110426  
 178A      1.113573   179A      1.130046   180A      1.140163  
 181A      1.149466   182A      1.165064   183A      1.167808  
 184A      1.200331   185A      1.224587   186A      1.236374  
 187A      1.262267   188A      1.270340   189A      1.295961  
 190A      1.308886   191A      1.312194   192A      1.320348  
 193A      1.347916   194A      1.368024   195A      1.385492  
 196A      1.403198   197A      1.422831   198A      1.450147  
 199A      1.473220   200A      1.482167   201A      1.513629  
 202A      1.515925   203A      1.532244   204A      1.533742  
 205A      1.546476   206A      1.582869   207A      1.588035  
 208A      1.601877   209A      1.625148   210A      1.627036  
 211A      1.643862   212A      1.663294   213A      1.672634  
 214A      1.688311   215A      1.695870   216A      1.696276  
 217A      1.721673   218A      1.730300   219A      1.740454  
 220A      1.741593   221A      1.749957   222A      1.780014  
 223A      1.780921   224A      1.782073   225A      1.828089  
 226A      1.843363   227A      1.859159   228A      1.863690  
 229A      1.875412   230A      1.881727   231A      1.900616  
 232A      1.920295   233A      1.936816   234A      1.952257  
 235A      1.958313   236A      1.981189   237A      1.986842  
 238A      2.010869   239A      2.042037   240A      2.050374  
 241A      2.093521   242A      2.099123   243A      2.107456  
 244A      2.110368   245A      2.122066   246A      2.137166  
 247A      2.150374   248A      2.159139   249A      2.177966  
 250A      2.189065   251A      2.208531   252A      2.230480  
 253A      2.232836   254A      2.242528   255A      2.270840  
 256A      2.278619   257A      2.284602   258A      2.297334  
 259A      2.324590   260A      2.329846   261A      2.341018  
 262A      2.343733   263A      2.376148   264A      2.390898  
 265A      2.399941   266A      2.408476   267A      2.456883  
 268A      2.471365   269A      2.511895   270A      2.559712  
 271A      2.564160   272A      2.578156   273A      2.606564  
 274A      2.646232   275A      2.646532   276A      2.657162  
 277A      2.731953   278A      2.736702   279A      2.760865  
 280A      2.784950   281A      2.871492   282A      2.882803  
 283A      2.884905   284A      2.901738   285A      2.939416  
 286A      2.950437   287A      2.993824   288A      3.026321  
 289A      3.034888   290A      3.080560   291A      3.115528  
 292A      3.160830   293A      3.204109   294A      3.220650  
 295A      3.255507   296A      3.299135   297A      3.372999  
 298A      3.406937   299A      3.470602   300A      3.601494  
 301A      3.661332   302A      3.728045   303A      3.745729  
 304A      3.754445   305A      3.776794   306A      3.792713  
 307A      3.809409   308A      3.856205   309A      3.919164  
 310A      3.954443   311A      4.025547   312A      4.081390  
 313A      4.227598   314A      4.388499   315A      4.450966  
 316A      4.758385  

Final Occupation by Irrep:
          A 
DOCC [    39 ]

@RHF Final Energy: -511.25468245359821

=> Energetics <=

Nuclear Repulsion Energy =            577.9090700035203554
One-Electron Energy =               -1843.1474439583616913
Two-Electron Energy =                 753.9836915012431291
Total Energy =                       -511.2546824535982068

Computation Completed

Properties will be evaluated at 0.000000, 0.000000, 0.000000 [a0]

Properties computed using the SCF density matrix

Nuclear Dipole Moment: [e a0]
X: 2.8568 Y: 1.3964 Z: 0.0121

Electronic Dipole Moment: [e a0]
X: -2.2107 Y: -0.9969 Z: -0.0165

Dipole Moment: [e a0]
X: 0.6461 Y: 0.3995 Z: -0.0044 Total: 0.7597

Dipole Moment: [D]
X: 1.6423 Y: 1.0154 Z: -0.0111 Total: 1.9309

*** tstop() called on chemcompute-node-0.novalocal at Sat Mar 15 13:43:05 2025
Module time:
user time = 254.18 seconds = 4.24 minutes
system time = 23.21 seconds = 0.39 minutes
total time = 88 seconds = 1.47 minutes
Total time:
user time = 254.18 seconds = 4.24 minutes
system time = 23.21 seconds = 0.39 minutes
total time = 88 seconds = 1.47 minutes
MINTS: Wrapper to libmints.
by Justin Turney

Calculation information:
Number of threads: 8
Number of atoms: 18
Number of AO shells: 134
Number of SO shells: 134
Number of primitives: 324
Number of atomic orbitals: 338
Number of basis functions: 316

  Number of irreps:                  1
  Integral cutoff                 1.00e-12
  Number of functions per irrep: [ 316 ]

OEINTS: Overlap, kinetic, potential, dipole, and quadrupole integrals
stored in file 35.

  Computing two-electron integrals...done
  Computed 1100884772 non-zero two-electron integrals.
    Stored in file 33.

*** tstart() called on chemcompute-node-0.novalocal
*** at Sat Mar 15 13:46:00 2025

Wfn Parameters:
--------------------
Wavefunction         = CCSD
Number of irreps     = 1
Number of MOs        = 316
Number of active MOs = 316
AO-Basis             = NONE
Semicanonical        = false
Reference            = RHF
Print Level          = 1

IRREP	# MOs	# FZDC	# DOCC	# SOCC	# VIRT	# FZVR
-----	-----	------	------	------	------	------
 A	   316	    0	    39	    0	    277	    0
Transforming integrals...
IWL integrals will be deleted.
(OO|OO)...
Presorting SO-basis two-electron integrals.
Sorting File: SO Ints (nn|nn) nbuckets = 1
Constructing frozen core operators
Starting first half-transformation.
Sorting half-transformed integrals.
First half integral transformation complete.
Starting second half-transformation.
Two-electron integral transformation complete.
(OO|OV)...
Starting second half-transformation.
Two-electron integral transformation complete.

I suspect your output is incomplete, and I also don’t understand why there were so many extraneous triple backticks.

The value of E should be the CCSD energy.

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jmisiewicz, thank you for your response. I don’t know why these backticks appeared, but I think I found that the molecular orbital energies in coupled cluster theory are the same as Hartree-Fock, as they only affect the total electronic energy. Therefore, it seems appropriate to rely on density functional theory (DFT) with long-range corrections to obtain more accurate HOMO, LUMO, and other orbital energies. As for these output total electronic energy values output by Psi4 , I’m not sure if they are Hartree-Fock or coupled cluster singles and doubles (CCSD).

  1. “more accurate orbital energies” isn’t a theoretically meaningful concept, but for what you probably want, you’d be better served by doing DFT, yes. Orbitals are not physical observables but very useful intermediates in the math of electronic structure theory. There is no experiment in the world that can tell you the shape of an orbital or what the energy of an orbital is. Now, there are physical experiments that can tell you the difference in electron density or energy between two electronic states, and these often can be interpreted in terms of orbitals. I don’t know what interpretations you’re trying to do, but CCSD does not change the orbitals compared to Hartree-Fock, and DFT orbitals are normally better for those purposes than HF orbitals. Please do a search of the literature for DFT orbitals in your particular task.
  2. The value of E in your script is the total CCSD energy, like I already said. If you mean something different by “these output total electronic energy values,” then you need to elaborate on what exactly you mean.
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Thank you for your insightful comment. What I aim to employ is what is of interest from a chemist’s perspective, where emission or absorption spectra are viewed as the energy difference between orbitals, or perhaps the energy difference between total states. This will help me, if I am not mistaken, in the engineering of a coordination complex, where the lowest excitation state is the ligand to the metal, not between the ligand to the ligand, when I perform non-extensive calculations and compare the HOMO and LUMO between parts of the coordination complex. Then, I will move on to time-dependent density functional theory. Logically, I tend to think that each orbital has an energy, which may not be the molecular orbital but rather the natural bonding orbital?"

Okay, if you want to look at the LUMO and HOMO as a cheap qualitative estimate on excited states, then yes, DFT is going to be your best option.

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