[molpro-user] SACASSCF in MOLPRO & ORCA

Davood Alizadeh alizadeh_davood at yahoo.com
Tue Jan 13 09:27:57 GMT 2015


Dear Molpro experts,
Please accept my apologies for my long message. I try to be as concise as possible.   

I`m trying to calculate the excitation energies (EEs) of a diatomic molecule (FeAg) using the Molpro and ORCA quantum chemistry packages. What I`m willing to obtain is "identical" excitation energies with these two codes. Despite the slight, at least in my opinion, differences in the SA-CASSCF optimization algorithms implemented in these two codes (e.g.,1) CSF-based optimization of ORCA Vs determinant-based optimization of Molpro in SA-CASSCF calculations
2) non-linear coupled optimization of molpro (Werner) Vs uncoupled optimizations (Newton-Rouphson, DIIS, ...) of ORCA...)
I`m employing identical basis sets, active spaces, inactive (closed) spaces, etc in these two programs. Thus, I think expecting identical results (either energy deference or absolute energies) might be totally warranted. 

The thing is this is the case "just" for a CAS space of (9e,7o) spanned by the atomic {molecular} representations (4s3d^Fe) and (5s^Ag) {sig(3), delta, and pi}, i.e., using this active space, these two codes give identical EEs and absolute energies. However, when the full valence space of (19e,12o), consisting of (4s3d^Fe) and (5s4d^Ag) {sig(4), delta (2), and pi(2)} which is a more adequate/realistic one, is used the Molpro results show considerably different EEs from those of ORCA. I need to confess that these differences which is about 2500 cm^-1 (at the worst case) cannot be considered "huge" but closer results are required for the system at hand.
I think, basically, these discrepancies between EEs of the two codes is due to the following compositions of natural MOs (in irrep A_1) optimized at the CAS(19e,12o) level of theory (from 15.1 to 20.1 is active): Orb     Occ        Energy       Coefficients++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

                                                     1 1s      1 1s      1 1s      1 1s      1 1s      1 1s      1 1s      1 1s      1 1s      1 1s   
                                                     1 1s      1 1s      1 1s      1 1s      1 2pz     1 2pz     1 2pz     1 2pz     1 2pz     1 2pz  
                                                     1 2pz     1 2pz     1 2pz     1 2pz     1 3d0     1 3d2+    1 3d0     1 3d2+    1 3d0     1 3d2+ 
                                                     1 3d0     1 3d2+    1 3d0     1 3d2+    1 4f0     1 4f2+    1 4f0     1 4f2+    1 4f0     1 4f2+ 
                                                     1 5g0     1 5g4+    1 5g2+    2 1s      2 1s      2 1s      2 1s      2 1s      2 1s      2 1s   
                                                     2 1s      2 1s      2 1s      2 1s      2 1s      2 2pz     2 2pz     2 2pz     2 2pz     2 2pz  
                                                     2 2pz     2 2pz     2 2pz     2 2pz     2 3d0     2 3d2+    2 3d0     2 3d2+    2 3d0     2 3d2+ 
                                                     2 3d0     2 3d2+    2 3d0     2 3d2+ 
  14.1  2.00000    -0.502146    -0.001015 -0.000011 -0.000088 -0.000423 -0.001134  0.000337  0.004706  0.006334 -0.002624 -0.014412
                                                    -0.011738  0.002893  0.090524 -0.033874  0.003529  0.000112  0.000271 -0.002368 -0.007818 -0.001503
                                                    -0.007113  0.037722  0.036990 -0.018287  0.007173  0.000000  0.006388  0.000000  0.000198  0.000000
                                                     0.024728  0.000000 -0.004631  0.000000  0.000080  0.000000  0.000223  0.000000  0.002026  0.000000
                                                     0.000075  0.000000  0.000000 -0.000033 -0.000004 -0.000017  0.000296  0.000680 -0.000543 -0.001423
                                                     0.001182 -0.001467  0.004694 -0.002035 -0.035825  0.000509  0.000045 -0.000310 -0.002299  0.003527
                                                    -0.005320  0.011943 -0.011928  0.043778 -0.253219  0.000000  0.010008  0.000000  0.370894  0.000000
                                                     0.493947  0.000000  0.310074  0.000000

  15.1  2.00000    -0.498811     0.000000  0.000000  0.000000  0.000000  0.000000  0.000000  0.000000  0.000000  0.000000  0.000000
                                                     0.000000  0.000000  0.000000  0.000000  0.000000  0.000000  0.000000  0.000000  0.000000  0.000000
                                                     0.000000  0.000000  0.000000  0.000000  0.000000  0.000815  0.000000 -0.000031  0.000000  0.001877
                                                     0.000000 -0.003179  0.000000  0.013680  0.000000  0.000047  0.000000 -0.000177  0.000000  0.001064
                                                     0.000000  0.000000  0.000021  0.000000  0.000000  0.000000  0.000000  0.000000  0.000000  0.000000
                                                     0.000000  0.000000  0.000000  0.000000  0.000000  0.000000  0.000000  0.000000  0.000000  0.000000
                                                     0.000000  0.000000  0.000000  0.000000  0.000000 -0.254068  0.000000  0.010335  0.000000  0.375990
                                                     0.000000  0.494604  0.000000  0.320878

  16.1  1.99873    -2.707087    -0.000010  0.000000 -0.000001 -0.000009 -0.000011 -0.000013  0.000187  0.000148  0.000024 -0.001313
                                                     0.000525 -0.000108  0.001382  0.000143  0.325725  0.004979  0.020291 -0.245961 -0.476994 -0.390804
                                                    -0.094062  0.000806 -0.001811  0.000502  0.000440  0.000000  0.000508  0.000000 -0.000169  0.000000
                                                     0.000107  0.000000  0.000089  0.000000  0.000020  0.000000  0.000058  0.000000 -0.000115  0.000000
                                                    -0.000008  0.000000  0.000000 -0.000048 -0.000007 -0.000019  0.000164  0.000127  0.000039 -0.000312
                                                    -0.000632  0.000584  0.000997 -0.000840 -0.001190 -0.000553 -0.000036  0.000598  0.001010  0.000225
                                                    -0.001080 -0.002101 -0.000195  0.000712 -0.001950  0.000000  0.000078  0.000000  0.002893  0.000000
                                                     0.003809  0.000000  0.002121  0.000000...
 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++These compositions show that the optimized reference space is spanned by 15.1 (4d^Ag), 16.1 (2p^Fe) ... and the 14.1(4d^Ag) is turned out to be a core orbital whereas it is expected to have this orbital in the active space! The same happens for B_1 and B_2 irreps. 

This is my input by the way:
 

 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++   SET,DKROLL=1
 
   {rhf
   wf,73,4,5;
  occ,20,8,8,3;
  closed,17,7,7,2
  orbital,2100.2
  }
 
  {casscf;occ,20,8,8,3;closed,16,7,7,2
 { ITERATIONS;
 DO,internal,2,TO,20;
 }
    start,2100.2;
    WF,73,1,3;state,3
    WF,73,2,3;state,3
    WF,73,3,3;state,3
    WF,73,4,3;state,3
    WF,73,1,5;state,3
    WF,73,2,5;state,3
    WF,73,3,5;state,3
    WF,73,4,5;state,3
  expec2,lxx,lyy,lzz;
  natorb,ci,print;
  ORBITAL,2140.2;
   }
 
  {casscf;occ,20,8,8,3;closed,14,6,6,1
 { ITERATIONS;
 DO,internal,2,TO,20;
 }
     start,2140.2;
    WF,73,1,3;state,3
    WF,73,2,3;state,3
    WF,73,3,3;state,3
    WF,73,4,3;state,3
    WF,73,1,5;state,3
    WF,73,2,5;state,3
    WF,73,3,5;state,3
    WF,73,4,5;state,3
  expec2,lxx,lyy,lzz;
  natorb,ci,print;
  ORBITAL,2140.2;
   }
 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 Could someone help me about this problem please?




Thanks a lot in advance,sincerely yours.Davood.  


  
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