[Pw_forum] problems on spin polarized lowdin charges

[Y.M.Qian]

Dear PWSCF user 

Recently  I am doing calculation to get the magnetic moment of each atom of a given crystal SrCrO3 . I follow the steps of previous mail about " Magnetic moment on each atom " .
1 SCF  
2 nscf  
3 projwfc

and get the information from the output file 

Lowdin Charges:
     Atom #   1: total charge =   9.5544, s =  1.9621, p =  6.3724, d =  1.2199,
                 spin up      =   4.7911, s =  0.9832, p =  3.1883, d =  0.6196,
                 spin down    =   4.7633, s =  0.9789, p =  3.1841, d =  0.6003,
                 polarization =   0.0277, s =  0.0043, p =  0.0042, d =  0.0192,
     Atom #   2: total charge =  13.4411, s =  2.1863, p =  6.8075, d =  4.4473,
                 spin up      =   7.6579, s =  1.0967, p =  3.4108, d =  3.1504,
                 spin down    =   5.7832, s =  1.0896, p =  3.3967, d =  1.2968,
                 polarization =   1.8748, s =  0.0070, p =  0.0141, d =  1.8536,
     Atom #   3: total charge =   6.3147, s =  1.5461, p =  4.7686, d =  0.0000,
                 spin up      =   3.1680, s =  0.7732, p =  2.3948, d =  0.0000,
                 spin down    =   3.1466, s =  0.7729, p =  2.3738, d =  0.0000,
                 polarization =   0.0214, s =  0.0003, p =  0.0210, d =  0.0000,
     Atom #   4: total charge =   6.3147, s =  1.5461, p =  4.7686, d =  0.0000,
                 spin up      =   3.1680, s =  0.7732, p =  2.3948, d =  0.0000,
                 spin down    =   3.1466, s =  0.7729, p =  2.3738, d =  0.0000,
                 polarization =   0.0214, s =  0.0003, p =  0.0210, d =  0.0000,
     Atom #   5: total charge =   6.3147, s =  1.5461, p =  4.7686, d =  0.0000,
                 spin up      =   3.1680, s =  0.7732, p =  2.3948, d =  0.0000,
                 spin down    =   3.1466, s =  0.7729, p =  2.3738, d =  0.0000,
                 polarization =   0.0214, s =  0.0003, p =  0.0210, d =  0.0000,
     Spilling Parameter:   0.0014

The second atom is transition metal Cr , large magnetic moment appears . But according to the 
chemical composition of the compound SrCrO3 , there should be two electrons that occupy the 
d orbitals . But here  the results shows there are 4.4473 electrons that occupy d orbitals .
1   Why is  so large number of electrons that occupy d orbitals ? Is there any one know how to explain this discrepancy ? 


I also read the tips from Frequently Asked Questions (FAQ) and the correspond reference Sanchez-Portal et al., Sol. State Commun. 95, 685 (1995).  

Though absolute number of  charge that projected to the d orbitals lack clear physical meaning ,currently  , but the absolute value of difference of spin-up and spin-down charge have clear physical meaning : magnetic moment .  So if the charge on atoms can't be calcualted accurately 
2 how to determine the magnetic moment accurately?
    

your sincerely 
Yumin Qian 
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