NdFeO3晶体的单点计算SCF不收敛

nusiew

大家好，我利用cp2k做NdFeO3晶体的单点计算，设置了UKS+Smear+MAGNETIZATION，发现SCF不收敛，将&MIXING中的alpha在0.01~0.6之间的取值都尝试了，发现仍不能收敛，也尝试对Fe取不同的MAGNETIZATION，发现也不行。Materials Project上显示的NdFeO3的磁矩为1.000 μB，磁序为铁磁性FM，我将Fe的MAGNETIZATION都取为4，或者按所处的环境将Fe分为两类，分别取为3和4（也取过1和2），发现仍不行。现在不知道怎么修改参数了，请大家多多指导！谢谢大家。

1. #Generated by Multiwfn
   
2. &GLOBAL
   
3.   PROJECT NdFeO3
   
4.   PRINT_LEVEL MEDIUM
   
5.   RUN_TYPE ENERGY
   
6. &END GLOBAL
   
7. 
   
8. &FORCE_EVAL
   
9.   METHOD Quickstep
   
10.   &SUBSYS
    
11.     &TOPOLOGY
    
12.       MULTIPLE_UNIT_CELL  2  2  1
    
13.     &END TOPOLOGY
    
14.     &CELL
    
15.       A     5.45320000     0.00000000     0.00000000
    
16.       B     0.00000000     5.58900000     0.00000000
    
17.       C     0.00000000     0.00000000     7.76770000
    
18.       MULTIPLE_UNIT_CELL  2  2  1
    
19.       PERIODIC XYZ #Direction of applied PBC (geometry aspect)
    
20.     &END CELL
    
21.     &COORD
    
22.       Nd       5.39485076    0.27274320    1.94192500
    
23.       Fe_1       5.45320000    2.79450000    0.00000000
    
24.       O        0.47770032    2.65980510    1.94192500
    
25.       O        3.84559664    1.64093040    0.35886774
    
26.       Nd       2.78494924    3.06724320    1.94192500
    
27.       Fe       2.72660000    0.00000000    0.00000000
    
28.       O        2.24889968    5.45430510    1.94192500
    
29.       O        4.33420336    4.43543040    0.35886774
    
30.       Fe       5.45320000    2.79450000    3.88385000
    
31.       O        3.84559664    1.64093040    3.52498226
    
32.       Nd       2.66825076    2.52175680    5.82577500
    
33.       Fe_1       2.72660000    0.00000000    3.88385000
    
34.       O        3.20430032    0.13469490    5.82577500
    
35.       O        1.11899664    1.15356960    4.24271774
    
36.       Nd       0.05834924    5.31625680    5.82577500
    
37.       O        4.97549968    2.92919490    5.82577500
    
38.       O        1.60760336    3.94806960    7.40883226
    
39.       O        1.11899664    1.15356960    7.40883226
    
40.       O        1.60760336    3.94806960    4.24271774
    
41.       O        4.33420336    4.43543040    3.52498226
    
42.     &END COORD
    
43.     &KIND O   
    
44.       ELEMENT O
    
45.       BASIS_SET DZVP-MOLOPT-SR-GTH-q6
    
46.       POTENTIAL GTH-PBE
    
47.       # MAGNETIZATION  0.6
    
48.     &END KIND
    
49.     &KIND Fe_1   
    
50.       ELEMENT Fe
    
51.       BASIS_SET DZVP-MOLOPT-SR-GTH-q16
    
52.       POTENTIAL GTH-PBE
    
53.       #&DFT_PLUS_U T
    
54.       #  L 2 #Quantum number of angular momentum the atomic orbitals to +U. 2=d, 3=f
    
55.       #  U_MINUS_J [eV] 4.0 #Effective on-site Coulomb interaction parameter U(eff) = U - J
    
56.       #&END DFT_PLUS_U
    
57.       MAGNETIZATION  3.0
    
58.     &END KIND
    
59.     &KIND Fe   
    
60.       ELEMENT Fe
    
61.       BASIS_SET DZVP-MOLOPT-SR-GTH-q16
    
62.       POTENTIAL GTH-PBE
    
63.       #&DFT_PLUS_U T
    
64.       #  L 2 #Quantum number of angular momentum the atomic orbitals to +U. 2=d, 3=f
    
65.       #  U_MINUS_J [eV] 4.0 #Effective on-site Coulomb interaction parameter U(eff) = U - J
    
66.       #&END DFT_PLUS_U
    
67.       MAGNETIZATION  4.0
    
68.     &END KIND
    
69.     &KIND Nd   
    
70.       ELEMENT Nd
    
71.       BASIS_SET DZVP-MOLOPT-SR-GTH-q14
    
72.       POTENTIAL GTH-PBE
    
73.       #&DFT_PLUS_U T
    
74.       #  L 2 #Quantum number of angular momentum the atomic orbitals to +U. 2=d, 3=f
    
75.       #  U_MINUS_J [eV] 1e-20 #Effective on-site Coulomb interaction parameter U(eff) = U - J
    
76.       #&END DFT_PLUS_U
    
77.       # MAGNETIZATION  0.6
    
78.     &END KIND
    
79.   &END SUBSYS
    
80. 
    
81.   &DFT
    
82. #    BASIS_SET_FILE_NAME BASIS_MOLOPT
    
83.     BASIS_SET_FILE_NAME BASIS_MOLOPT_UCL
    
84. #    POTENTIAL_FILE_NAME GTH_POTENTIALS
    
85.     BASIS_SET_FILE_NAME  BASIS_MOLOPT
    
86.     POTENTIAL_FILE_NAME  POTENTIAL
    
87. #   WFN_RESTART_FILE_NAME NdFeO3-RESTART.wfn
    
88.     CHARGE    0 #Net charge
    
89.     # MULTIPLICITY   25 #Spin multiplicity
    
90.     UKS
    
91.     #RELAX_MULTIPLICITY 0.1
    
92.     # PLUS_U_METHOD MULLIKEN #The method used in DFT+U. Can also be Lowdin
    
93.     &QS
    
94.       EPS_DEFAULT 1E-10 #This is default. Set all EPS_xxx to values such that the energy will be correct up to this value
    
95.     &END QS
    
96.     &POISSON
    
97.       PERIODIC XYZ #Direction(s) of PBC for calculating electrostatics
    
98.       PSOLVER PERIODIC #The way to solve Poisson equation
    
99.     &END POISSON
    
100.     &XC
     
101.       &XC_FUNCTIONAL PBE
     
102.       &END XC_FUNCTIONAL
     
103.       &VDW_POTENTIAL
     
104.         POTENTIAL_TYPE PAIR_POTENTIAL
     
105.         &PAIR_POTENTIAL
     
106.           PARAMETER_FILE_NAME dftd3.dat
     
107.           TYPE DFTD3
     
108.           REFERENCE_FUNCTIONAL PBE
     
109.         &END PAIR_POTENTIAL
     
110.       &END VDW_POTENTIAL
     
111.     &END XC
     
112.     &MGRID
     
113.       CUTOFF 350
     
114.       REL_CUTOFF 50
     
115.     &END MGRID
     
116.     &SCF
     
117.       MAX_SCF 128
     
118.       EPS_SCF 5.0E-06 #Convergence threshold of density matrix during SCF
     
119. #     SCF_GUESS RESTART #Use wavefunction from WFN_RESTART_FILE_NAME file as initial guess
     
120.       &DIAGONALIZATION
     
121.         ALGORITHM STANDARD #Algorithm for diagonalization. DAVIDSON is faster for large systems
     
122.       &END DIAGONALIZATION
     
123.       &MIXING #How to mix old and new density matrices
     
124.         METHOD BROYDEN_MIXING #PULAY_MIXING is also a good alternative
     
125.         ALPHA 0.1 #Default. Mixing 40% of new density matrix with the old one
     
126.         NBROYDEN 8 #Default is 4. Number of previous steps stored for the actual mixing scheme
     
127.       &END MIXING
     
128.       &SMEAR
     
129.         METHOD FERMI_DIRAC
     
130.         ELECTRONIC_TEMPERATURE 300 #Electronic temperature of Fermi-Dirac smearing in K
     
131.       &END SMEAR
     
132.       ADDED_MOS   300   300 #Number of virtual MOs to solve for alpha and beta spins
     
133.     &END SCF
     
134.     &PRINT
     
135.       &DOS
     
136.       &END DOS
     
137.       &PDOS
     
138.           NLUMO -1
     
139.           COMPONENTS
     
140.       &END PDOS   
     
141.       &MO_MOLDEN #Exporting .molden file containing wavefunction information
     
142.         NDIGITS 9 #Output orbital coefficients if absolute value is larger than 1E-9
     
143.         GTO_KIND SPHERICAL #Spherical-harmonic type of basis functions
     
144.       &END MO_MOLDEN
     
145.       &ELF_CUBE
     
146.         STRIDE 1 #Stride of exported cube file
     
147.       &END ELF_CUBE
     
148.       &MULLIKEN
     
149.         PRINT_ALL F #If T, then printing full net AO and overlap population matrix
     
150.       &END MULLIKEN
     
151.       &MOMENTS
     
152.         PERIODIC T #Use Berry phase formula (T) or simple operator (F), the latter normally applies to isolated systems
     
153.       &END MOMENTS
     
154.     &END PRINT
     
155.   &END DFT
     
156. &END FORCE_EVAL
     

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sobereva

超胞用得太小，各个方向建议>=15埃
如果不打算+U或OT，用原胞结合k点计算划算得多
也可以尝试OT

nusiew

sobereva 发表于 2022-10-5 18:55
超胞用得太小，各个方向建议>=15埃
如果不打算+U或OT，用原胞结合k点计算划算得多
也可以尝试OT

谢谢卢老师的指导。采用3*3*3的超胞仍然不能够使得SCF收敛，由于想要计算该晶体的PDOS，所以要+U且只能扩胞。由于现在还是不能够收敛，请问卢老师还能如何改进？