Dear whom it may concern,
Thank you very much always for your help!
First I tried to converge r2SCAN in a 800 atom system (Al2O3-SiO2 pore) using ALGO=All and TIME=0.05. A slow convergence was observed, probably due to a large TIME, that is, the energy increases and decreases and fluctuates.
For a test calculation, I tested a H2O molecule in vacuum using ALGO=All and IALGO=54 (damped MD, velocity quenched or quickmin), which is less sensitive to TIME according to the vasp wiki. The energy did not increase much but decreased as expected. Interestingly the convered forces differ by an order of 0.1 eV/Ang. Is it okay? For the original 800 atom case, I'll try TIME=0.01, but this post is for others who may use IALGO=54.
Below are input files:
POSCAR
Code: Select all
O H
1.0000000000000000
13.0000000000000000 0.0000000000000000 0.0000000000000000
0.0000000000000000 13.0000000000000000 0.0000000000000000
0.0000000000000000 0.0000000000000000 13.0000000000000000
O H
1 2
Cartesian
4.0000000000000000 6.0000000000000000 6.3975400000000002
4.0000000000000000 6.7632399999999997 5.8012300000000003
4.0000000000000000 5.2367600000000003 5.8012300000000003
POTCARS:
POTCAR: PAW_PBE O 08Apr2002
POTCAR: PAW_PBE H 15Jun2001
1) ALGO=All
INCAR
Code: Select all
ISTART = 0
SYSTEM = H2O
ENCUT = 600 ! 1.5 ENMAX of O ( 400 )
PREC = Accurate
ALGO = All # 700 atoms, r2SCAN
TIME = 0.05
NELM = 400 # max electronic steps. slow convergence
GGA_COMPAT = F
LREAL = A
METAGGA = R2SCAN
LASPH = T
ISMEAR = 0 ! Gaussian
SIGMA = 0.1 ! eV
KSPACING = 0.52 # a < 12 Ang: 2x2x2, otherwise gamma. For > 200 kpt atom.
NCORE = 18
ISIF = 2 ! calculate stress, relax ions, keep cell
LWAVE = F
LCHARG = F
NWRITE = 0 # For a large job, save space. Force at the first ionic step.
2) IALGO=54 (damped MD, velocity quenched or quickmin) : only the ALGO tag was removed and the IALGO tag was included.
Code: Select all
ISTART = 0
SYSTEM = H2O
ENCUT = 600 ! 1.5 ENMAX of O ( 400 )
PREC = Accurate
IALGO = 54 # quick min
TIME = 0.05
NELM = 400 # max electronic steps. slow convergence
GGA_COMPAT = F
LREAL = A
METAGGA = R2SCAN
LASPH = T
ISMEAR = 0 ! Gaussian
SIGMA = 0.1 ! eV
KSPACING = 0.52 # a < 12 Ang: 2x2x2, otherwise gamma. For > 200 kpt atom.
NCORE = 18
ISIF = 2 ! calculate stress, relax ions, keep cell
LWAVE = F
LCHARG = F
NWRITE = 0 # For a large job, save space. Force at the first ionic step.
Below are converged forces: see the z component of the 1st atom changed from -0.365 to -0.44.
1) ALGO=All
Code: Select all
POSITION TOTAL-FORCE (eV/Angst)
-----------------------------------------------------------------------------------
4.00000 6.00000 6.39754 -0.000000 0.000000 -0.365369
4.00000 6.76324 5.80123 0.000000 -0.159017 0.182685
4.00000 5.23676 5.80123 -0.000000 0.159017 0.182685
-----------------------------------------------------------------------------------
total drift: 0.000010 -0.000010 -0.001770
2) IALGO=54 (damped MD)
Code: Select all
POSITION TOTAL-FORCE (eV/Angst)
-----------------------------------------------------------------------------------
4.00000 6.00000 6.39754 0.000000 -0.000000 -0.441665
4.00000 6.76324 5.80123 -0.000000 -0.159572 0.220833
4.00000 5.23676 5.80123 -0.000000 0.159572 0.220833
-----------------------------------------------------------------------------------
total drift: 0.000010 -0.000010 -0.135618
Additionally, these are OSZICAR's, and here we see that energy decreases for the both cases:
1) ALGO=All
Code: Select all
N E dE d eps ncg rms ort
DAV: 1 0.581741031911E+02 0.58174E+02 -0.18822E+03 8 0.501E+02
DAV: 2 -0.113070093572E+02 -0.69481E+02 -0.69481E+02 8 0.127E+02
DAV: 3 -0.197597343557E+02 -0.84527E+01 -0.84527E+01 8 0.620E+01
DAV: 4 -0.198934556826E+02 -0.13372E+00 -0.13372E+00 8 0.854E+00
DAV: 5 -0.198935847656E+02 -0.12908E-03 -0.12908E-03 8 0.260E-01
SDA: 6 -0.129442185079E+02 0.69494E+01 -0.12908E-03 8 0.161E+02 0.000E+00
CGA: 7 -0.148101982169E+02 -0.18660E+01 -0.16011E-04 8 0.285E+01-0.515E+01
CGA: 8 -0.151539219623E+02 -0.34372E+00 -0.32281E+00 8 0.372E+00 0.159E+00
CGA: 9 -0.152347824471E+02 -0.80860E-01 -0.80384E-01 8 0.163E+00 0.144E-02
CGA: 10 -0.152961538547E+02 -0.61371E-01 -0.28828E-02 8 0.128E+00 0.204E-04
CGA: 11 -0.153278318929E+02 -0.31678E-01 -0.31096E-01 8 0.267E-01 0.196E-02
CGA: 12 -0.153340004275E+02 -0.61685E-02 -0.61703E-02 8 0.665E-02-0.291E-04
CGA: 13 -0.153358452092E+02 -0.18448E-02 -0.18457E-02 8 0.215E-02-0.425E-05
CGA: 14 -0.153364554424E+02 -0.61023E-03 -0.60955E-03 8 0.560E-03 0.683E-05
CGA: 15 -0.153366075001E+02 -0.15206E-03 -0.15205E-03 8 0.143E-03 0.385E-06
CGA: 16 -0.153366552644E+02 -0.47764E-04 -0.47904E-04 8 0.531E-04-0.799E-06
1 F= -.15336655E+02 E0= -.15336655E+02 d E =-.244881E-12
2) IALGO=54 (damped MD)
Code: Select all
N E dE d eps ncg rms ort
DAV: 1 0.155601673409E+03 0.15560E+03 -0.89953E+02 8 0.501E+02
DAV: 2 0.916370191975E+02 -0.63965E+02 -0.63964E+02 8 0.135E+02
DAV: 3 0.474284007478E+02 -0.44209E+02 -0.44207E+02 8 0.111E+02
DAV: 4 0.194504862141E+01 -0.45483E+02 -0.45482E+02 8 0.191E+02
DAV: 5 -0.138562881141E+02 -0.15801E+02 -0.15801E+02 8 0.120E+02
SDA: 6 -0.894666041969E+01 0.49096E+01 -0.11280E+01 8 0.226E+02 0.000E+00
QMN: 7 -0.100157802299E+02 -0.10691E+01 -0.18714E+01 8 0.172E+02 0.202E+02
QMN: 8 -0.116790697546E+02 -0.16633E+01 -0.19696E+01 8 0.104E+02 0.290E+02
QMN: 9 -0.132570986338E+02 -0.15780E+01 -0.14367E+01 8 0.524E+01 0.235E+02
QMN: 10 -0.141574985973E+02 -0.90040E+00 -0.54949E+00 8 0.405E+01 0.694E+01
QMN: 11 -0.141277629552E+02 0.29736E-01 -0.35276E+00 8 0.706E+01-0.126E+02
QMN: 12 -0.144492290462E+02 -0.32147E+00 -0.52224E+00 8 0.464E+01 0.581E+01
QMN: 13 -0.148746166428E+02 -0.42539E+00 -0.42407E+00 8 0.188E+01 0.660E+01
QMN: 14 -0.151519863679E+02 -0.27737E+00 -0.15287E+00 8 0.371E+00 0.269E+01
QMN: 15 -0.151536048171E+02 -0.16184E-02 -0.31563E-01 8 0.631E+00-0.289E+01
QMN: 16 -0.151831814476E+02 -0.29577E-01 -0.51005E-01 8 0.468E+00 0.552E+00
QMN: 17 -0.152275151193E+02 -0.44334E-01 -0.50476E-01 8 0.258E+00 0.752E+00
QMN: 18 -0.152665018838E+02 -0.38987E-01 -0.32585E-01 8 0.106E+00 0.546E+00
QMN: 19 -0.152850062681E+02 -0.18504E-01 -0.80012E-02 8 0.786E-01 0.814E-01
QMN: 20 -0.152797575114E+02 0.52488E-02 -0.89978E-02 8 0.180E+00-0.379E+00
QMN: 21 -0.152882074993E+02 -0.84500E-02 -0.14678E-01 8 0.136E+00 0.158E+00
QMN: 22 -0.153010398416E+02 -0.12832E-01 -0.14845E-01 8 0.769E-01 0.220E+00
QMN: 23 -0.153127032442E+02 -0.11663E-01 -0.10169E-01 8 0.327E-01 0.171E+00
QMN: 24 -0.153189388447E+02 -0.62356E-02 -0.34587E-02 8 0.207E-01 0.485E-01
QMN: 25 -0.153186367940E+02 0.30205E-03 -0.22117E-02 8 0.442E-01-0.768E-01
QMN: 26 -0.153207279267E+02 -0.20911E-02 -0.37232E-02 8 0.351E-01 0.394E-01
QMN: 27 -0.153240314024E+02 -0.33035E-02 -0.39743E-02 8 0.218E-01 0.577E-01
QMN: 28 -0.153272562413E+02 -0.32248E-02 -0.30319E-02 8 0.111E-01 0.495E-01
QMN: 29 -0.153293359807E+02 -0.20797E-02 -0.15293E-02 8 0.803E-02 0.226E-01
QMN: 30 -0.153299463725E+02 -0.61039E-03 -0.70096E-03 8 0.140E-01-0.612E-02
QMN: 31 -0.153306099841E+02 -0.66361E-03 -0.11803E-02 8 0.111E-01 0.125E-01
QMN: 32 -0.153316618785E+02 -0.10519E-02 -0.12795E-02 8 0.711E-02 0.185E-01
QMN: 33 -0.153327160560E+02 -0.10542E-02 -0.10379E-02 8 0.408E-02 0.167E-01
QMN: 34 -0.153334735810E+02 -0.75753E-03 -0.66105E-03 8 0.343E-02 0.979E-02
QMN: 35 -0.153338681101E+02 -0.39453E-03 -0.40987E-03 8 0.520E-02 0.299E-02
QMN: 36 -0.153340733798E+02 -0.20527E-03 -0.42142E-03 8 0.782E-02 0.612E-03
QMN: 37 -0.153343491220E+02 -0.27574E-03 -0.62748E-03 8 0.927E-02 0.328E-02
QMN: 38 -0.153348443286E+02 -0.49521E-03 -0.81438E-03 8 0.841E-02 0.788E-02
QMN: 39 -0.153354837923E+02 -0.63946E-03 -0.76865E-03 8 0.565E-02 0.973E-02
QMN: 40 -0.153360039924E+02 -0.52020E-03 -0.41322E-03 8 0.264E-02 0.562E-02
QMN: 41 -0.153361048646E+02 -0.10087E-03 -0.53433E-04 8 0.107E-02-0.422E-02
QMN: 42 -0.153361563750E+02 -0.51510E-04 -0.95742E-04 8 0.922E-03 0.993E-03
1 F= -.15336156E+02 E0= -.15336156E+02 d E =-.333902E-12
I do not know whether a r2SCAN calculation always should start from reading WAVECAR of converged PBE and should not start from scratch.
Thank you very much!
