[CP2K-user] Vxc for SIC

Xiaoming Wang wxia... at gmail.com
Fri Dec 27 16:50:58 UTC 2019


Hello all,

I'm trying to implement the SIC scheme proposed in PRB 99, 235139 (2019) by 
Giustino et al. 

The new SIC scheme is a minor modification on the one proposed by Mauri 
[PRB 71, 205210 (2005)]. 

Since the Mauri SIC is implemented in CP2K, incorporation of the Giustino 
scheme should not need 

much coding work. The Hartree self-interaction part is similar for all the 
schemes, so I'm only interested

in the XC part. The implementation of the XC part of the Mauri scheme is 
coded in qs_vxc.F. 

There are two types of SIC functionals for the Mauri scheme:  Mauri_SPZ and 
Mauri_US. 

The corresponding SIC corrrected XC functionals are:

         Mauri_SPZ: Exc = Exc [ alpha, beta ] - Exc [ alpha - beta, 0 ]

         Mauri_US:  Exc = Exc [ alpha, beta ] - Exc [ alpha, beta ] + Exc [ 
beta, beta ]

And the XC potentials are:

         Mauri_SPZ: Vxc_up = Vxc_up [ alpha, beta ] - Vxc_up [ alpha - 
beta, 0 ]
                             Vxc_dn = Vxc_dn [ alpha, beta ] + Vxc_up [ 
alpha - beta, 0 ]

         Mauri_US:  Vxc_up = 0
                            Vxc_dn = Vxc_up [ beta, beta ] +  Vxc_dn [ 
beta, beta ]

For the Giustino scheme, the XC functional is:

          Exc = 0.5*Exc [ alpha, beta ] + Exc [ beta, beta ] - 0.5* Exc [ 
beta - m, beta ]

where m = alpha - beta. Based on my understanding, the XC potentials are:

         Vxc_up = 0.5*Vxc_up [ alpha, beta ] + 0.5*Vxc_up [ beta - m, beta ]

         Vxc_dn = 0.5*Vxc_dn [ alpha, beta ] + Vxc_up [ beta, beta ] +  
Vxc_dn [ beta, beta ]
                       
                          -0.5*Vxc_dn [ beta - m, beta ] - Vxc_up [ beta - 
m, beta ]

Please can anyone correct me if my understanding above is wrong. 

I implemented the Giustino SIC based on the above equations by slightly 
modifying the US scheme 

as already in CP2K. However, I never get convergence for the SCF 
calculations (see part of the log

file below). For the same system, the SPZ and US schemes both can easily 
get convergence.

So I'm wondering if anyone could give me any comments on this?



Best,

Xiaoming



--
     1 OT CG       0.15E+00   14.2     0.00014039     -8153.9988425820 
-8.15E+03
     2 OT LS       0.10E+00    5.2                    -8154.0035499679
     3 OT CG       0.10E+00   10.6     0.00020232     -8154.0032891957 
-4.45E-03
     4 OT LS       0.46E-01    6.0                    -8154.0015689085
     5 OT CG       0.46E-01   10.8     0.00009816     -8154.0041296811 
-8.40E-04
     6 OT LS       0.31E-01    5.1                    -8154.0048751897
     7 OT CG       0.31E-01   13.1     0.00007670     -8154.0046628243 
-5.33E-04
     8 OT LS       0.26E-01    5.2                    -8154.0051281540
     9 OT CG       0.26E-01   12.0     0.00007395     -8154.0050568034 
-3.94E-04
    10 OT LS       0.21E-01    6.2                    -8154.0053917653
    11 OT CG       0.21E-01   11.2     0.00007210     -8154.0053264707 
-2.70E-04
    12 OT LS       0.16E-01    5.3                    -8154.0055646935
    13 OT CG       0.16E-01   10.4     0.00005042     -8154.0055112362 
-1.85E-04
    14 OT LS       0.15E-01    5.3                    -8154.0056327656
    15 OT CG       0.15E-01   11.4     0.00004942     -8154.0056270301 
-1.16E-04
    16 OT LS       0.14E-01    5.3                    -8154.0057343493
    17 OT CG       0.14E-01   11.5     0.00004857     -8154.0057262676 
-9.92E-05
    18 OT LS       0.13E-01    5.4                    -8154.0058189369
    19 OT CG       0.13E-01   10.7     0.00004785     -8154.0058097707 
-8.35E-05
    20 OT LS       0.11E-01    5.0                    -8154.0058883901
  ----------------------------------- OT 
---------------------------------------
  ----------------------------------- OT 
---------------------------------------
     1 OT CG       0.15E+00   21.8     0.00004727     -8154.0058790748 
-6.93E-05
     2 OT LS       0.11E+00    4.7                    -8154.0065750586
     3 OT CG       0.11E+00   10.9     0.00004074     -8154.0064374937 
-5.58E-04
     4 OT LS       0.13E+00    5.4                    -8154.0072008089
     5 OT CG       0.13E+00   11.3     0.00002783     -8154.0072885701 
-8.51E-04
     6 OT LS       0.51E+00    5.5                    -8154.0078327851
     7 OT CG       0.51E+00   11.1     0.00007874     -8154.0089341020 
-1.65E-03
     8 OT LS       0.21E+00    5.2                    -8154.0051598661
     9 OT CG       0.21E+00   11.3     0.00017344     -8154.0086760074  
2.58E-04
    10 OT LS       0.98E-01    5.3                    -8154.0049564999
    11 OT CG       0.98E-01   11.2     0.00006510     -8154.0082092588  
4.67E-04
    12 OT LS       0.58E-01    5.7                    -8154.0086320114
    13 OT CG       0.58E-01   10.8     0.00003585     -8154.0085028738 
-2.94E-04
    14 OT LS       0.10E+00    5.3                    -8154.0088394530
    15 OT CG       0.10E+00   12.0     0.00007085     -8154.0090772735 
-5.74E-04
    16 OT LS       0.44E-01    5.4                    -8154.0084763907
    17 OT CG       0.44E-01   11.1     0.00003408     -8154.0088708613  
2.06E-04
    18 OT LS       0.72E-01    5.3                    -8154.0090917387
    19 OT CG       0.72E-01   11.4     0.00005874     -8154.0092230991 
-3.52E-04
    20 OT LS       0.30E-01    5.5                    -8154.0089057509
  ----------------------------------- OT 
---------------------------------------
  ----------------------------------- OT 
---------------------------------------
     1 OT CG       0.15E+00   22.0     0.00001421     -8154.0091066057  
1.16E-04
     2 OT LS       0.18E+00    5.9                    -8154.0092180076
     3 OT CG       0.18E+00   10.7     0.00005904     -8154.0092398262 
-1.33E-04
     4 OT LS       0.96E-01    5.5                    -8154.0094065127
     5 OT CG       0.96E-01   11.2     0.00007661     -8154.0094075743 
-1.68E-04
     6 OT LS       0.42E-01    5.6                    -8154.0088928557
     7 OT CG       0.42E-01   10.9     0.00001444     -8154.0092323658  
1.75E-04
     8 OT LS       0.57E-01    5.1                    -8154.0092666992
     9 OT CG       0.57E-01   11.2     0.00001390     -8154.0092787816 
-4.64E-05
    10 OT LS       0.68E-01    5.2                    -8154.0093186446
    11 OT CG       0.68E-01   10.5     0.00002940     -8154.0093259578 
-4.72E-05
    12 OT LS       0.26E-01    5.0                    -8154.0092084126
    13 OT CG       0.26E-01   11.0     0.00001386     -8154.0092843540  
4.16E-05
    14 OT LS       0.13E-01    5.4                    -8154.0092839420
    15 OT CG       0.13E-01   11.0     0.00001387     -8154.0092841905  
1.64E-07
    16 OT LS       0.16E-01    5.4                    -8154.0092934733
    17 OT CG       0.16E-01   11.0     0.00001375     -8154.0092962332 
-1.20E-05
    18 OT LS       0.20E-01    5.4                    -8154.0093077912
    19 OT CG       0.20E-01   10.4     0.00001362     -8154.0093106170 
-1.44E-05
    20 OT LS       0.24E-01    5.3                    -8154.0093242773
  ----------------------------------- OT 
---------------------------------------
  ----------------------------------- OT 
---------------------------------------
     1 OT CG       0.15E+00   22.4     0.00001343     -8154.0093267803 
-1.62E-05
     2 OT LS       0.15E+00    5.4                    -8154.0094121812
     3 OT CG       0.15E+00   11.6     0.00007460     -8154.0094132278 
-8.64E-05
     4 OT LS       0.74E-01    5.3                    -8154.0093027278
     5 OT CG       0.74E-01   10.9     0.00007707     -8154.0094484130 
-3.52E-05
     6 OT LS       0.33E-01    5.6                    -8154.0090697156
     7 OT CG       0.33E-01   14.3     0.00001494     -8154.0093119312  
1.36E-04
     8 OT LS       0.46E-01    6.5                    -8154.0093411677

--



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