[molpro-user] Additional Electron Removed

[Gerald Knizia]

Dear Henry,
the MS2 quantum number which Molpro uses does not denote spin
multiplicity, but the number of unpaired electrons (i.e., the difference
in the number of Alpha and Beta electrons, assuming a high-spin
configuration).

This means:
  closed-shell is MS2=0
  high-spin doublet is MS2=1 (one unpaired electron)
  high-spin triplet is MS2=2 (two unpaired electrons)
etc.

You are telling your calculation to use spin=2, which means two unpaired
electrons. If you use wf,spin=1,charge=1,sym=2 instead, you will get one
removed pi electron.

Best wishes,
Gerald



On Thu, 2016-07-21 at 14:08 +0000, Banks, Henry wrote:
> Hello,
> 
> I have been trying to run the following input file, for an N2 molecule with a missing 2sigma_g electron and a missing 1pi_ux electron:
> 
> ***,nitrogenMol in pvtz** basis
> memory,500,m
> 
> print,orbitals,civector,basis
> 
> basis
> spd,n,cc-pvtz
> c;
> end
> 
> geomtyp=xyz
> geometry={
> 2
> n2
> n,0.0,0.0,-0.5
> n,0.0,0.0,0.5
> }
> 
> {hf,
> wf, nelec=12, symmetry=2, spin=2
> open, 2.1, 1.2;
>                                                                                                                                    
> —
> 
> However, the output is also removing the 3sigma_g electron.
> 
>    Orb  Occ    Energy  Couls-En    Coefficients
> 
>                                    1 1s      1 1s      1 1s      1 1s      1 2pz     1 2pz     1 2pz     1 3d0     1 3d2+    1 3d0  
>                                    1 3d2+ 
> 
>    1.1   2   -17.4288  -45.5656  1.000257  0.000940  0.000805 -0.001740  0.017674 -0.011843 -0.005534  0.000694 -0.000184 -0.001597
>                                 -0.000117
> 
>    2.1   +    -3.4403  -14.4180 -0.055712  0.841434  0.051748 -0.323713  0.774160 -0.154968 -0.281711  0.066684  0.005486  0.025282
>                                  0.004498
> 
>    3.1   +    -2.1793  -10.6230 -0.051299 -0.742071  0.004978  0.109501  1.167006 -0.192015 -0.387168  0.052521 -0.002944  0.020157
>                                 -0.005120
> 
>                                    1 2px     1 2px     1 2px     1 3d1+    1 3d1+ 
> 
>    1.2   +    -2.3309  -11.4162  1.139339 -0.070991 -0.341906  0.078791  0.075807
> 
>                                    1 2py     1 2py     1 2py     1 3d1-    1 3d1- 
> 
>    1.3   2    -2.1774  -11.2226  1.137146 -0.076347 -0.324470  0.069428  0.070882
> 
>                                    1 1s      1 1s      1 1s      1 1s      1 2pz     1 2pz     1 2pz     1 3d0     1 3d2+    1 3d0  
>                                    1 3d2+ 
> 
>    1.5   2   -17.4228  -45.5578  0.998063 -0.007148  0.001136 -0.002071  0.018119 -0.014963 -0.007288  0.001691 -0.000098 -0.001653
>                                 -0.000066
> 
>    2.5   2    -2.0716  -10.3375 -0.033567 -1.155713 -0.035948  0.082129  0.534475 -0.043132 -0.204977  0.016044 -0.001151  0.028985
>                                 -0.003226
> 
> Is there something missing from my input file? Or is there some other reason why an additional electron is being removed?
> 
> This calculation was run with Molpro 2015.1.5
> 
> Best,
> Henry Banks
> 
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