I did a convergence test for silica(SiO2) using all-electron calculation, and I got a quiet high converged cutoff (~1400 Ry) using GAPW method. The basis used are 6-31G* in EMSL_BASIS_SETS and pcseg-2 of ADMM. Could you please take a look at it and offer me suggestions to lower the cutoff? I have append ouput files and posted the input,
@SET project silica
@SET lib /home/yunai/M/E/SW/abInitio/cp2k/data/
&FORCE_EVAL
METHOD Quickstep
&DFT
BASIS_SET_FILE_NAME ${lib}EMSL_BASIS_SETS
POTENTIAL_FILE_NAME ${lib}POTENTIAL
&POISSON
PERIODIC XYZ
&END POISSON
&MGRID
CUTOFF 800
REL_CUTOFF 70
NGRIDS 4
&END MGRID
&QS
METHOD GAPW
EPS_DEFAULT 1.0E-10
EXTRAPOLATION ASPC
EXTRAPOLATION_ORDER 3
&END QS
&SCF
SCF_GUESS ATOMIC #ATOMIC
EPS_SCF 1.0E-6
MAX_SCF 100
&SMEAR ON
METHOD FERMI_DIRAC
ELECTRONIC_TEMPERATURE [K] 300
&END SMEAR
ADDED_MOS 100
&DIAGONALIZATION ON
ALGORITHM STANDARD
&END DIAGONALIZATION
&MIXING ON
METHOD BROYDEN_MIXING
ALPHA 0.4
# BETA 0.5
NBROYDEN 8
&END MIXING
&END SCF
&XC
&XC_FUNCTIONAL BLYP
&END XC_FUNCTIONAL
&END XC
&END DFT
&SUBSYS
&KIND Si
ELEMENT Si
BASIS_SET 6-31G**
POTENTIAL ALL
&END KIND
&KIND O
ELEMENT O
BASIS_SET 6-31G**
POTENTIAL ALL
&END KIND
&CELL
SYMMETRY CUBIC
A 9.7455633333 0.0 0.0
B 0.0 9.7455633333 0.0
C 0.0 0.0 9.7455633333
PERIODIC XYZ
&END CELL
&COORD
O 2.
7623936770 1.1137089509
1.6066876713 O 0.7356406653 2.1620228603 3.0361303865
Si
1.5304329216 2.1663388392 1.6201749328
O 2.1611027748 3.6247590288 1.3778772374
O 0.4771825457
1.8728089580 0.
4439819695 Si 3.1116787748 4.
7328010726 2.0595450356
O 3.
3398644261 4.
4458724425 3.6352291657
O 0.1270867544 3.0550850906 5.4393291440
O 3.
9419645493 3.7984593035 6.0724237956
O
1.8125652629 1.1555188032 6.0587535735
Si 4.
5749371264 4.0562467406 4.6150432346
O 4.
2209518137 0.2024218305 5.5072125827
O
1.7606021213 3.4293517879 7.4747736997
O -0.
2393841186 1.7614657701 7.6464234290
Si 0.8870879147 2.3400853460 6.
6579592354 Si 3.0276193444 4.
4076720098 7.2613483139
O 3.8937667585 4.4469244314 8.
6068027497 O 2.3541934146 6.1404600110 1.8909536216
O -0.1510841561 6.9275503716 2.
6199882599 Si 1.0903689604 7.0981208036
1.6067500379 O
1.6183890189 8.6032946232 1.8211843582
O 0.5527082293 6.
8724776780 0.0998574069
Si 3.0746197814 9.2866247259 1.7850569966
O 3.
9093635388 8.9469248092 3.1131160577
O 4.
5738417203 4.7157916949 1.3637765344
O 3.
9413455061 8.7662272645 0.5161904160
O 0.7909354039 6.
2243201162 4.9819467535
O 2.2150485098 8.2938588799 5.
8645698984 Si 1.4534705265 6.9268570999 6.2712148148
O 2.
5449034946 5.9204147174 6.9208632358
O 0.2612757810 7.2891739574 7.2994708402
Si 4.
4742182203 9.4566496378 8.8987446776
O 3.
2043255332 9.6942893869 7.9237510834
Si 2.
8563965372 9.7060931753 6.3395469239
O 6.2715397969 1.9820633297 1.7619455845
Si 6.3716860047 1.9672415320 0.1580264828
O 6.
2313329977 0.3313026593 3.7874773722
Si 9.3906054025 2.9813537251 3.
9078255520 O 5.
3214660859 2.7416025592 4.0803483450
O 7.9461117570 2.
2832099838 3.7987331647
Si 6.4602662916 1.8680222375 3.3520889825
O 9.
2536741476 4.5149786180 3.4110977981
Si 9.
3149559538 1.1133731944 9.1066267486
O 6.2481184898 3.
5067554443 9.4012946979
Si 5.1441421200 4.
6839056498 9.5929570832
O 5.1504752948 1.1351640314 9.
2485730410 O 7.7569502782 1.2663799887 9.
4786927189 Si 6.4512813548 6.
5189274958 5.2237888900
Si 9.3115993328 6.0463065346 3.
9375335741 O 5.
6803262812 5.2221590949 4.6856986549
Si 4.9840432668 9.1903545424 4.2924078131
O 5.5938407987 7.
8014279538 4.8006801089
O 7.9330633460 6.
5399536968 4.5989225537
O 7.9118825374 7.5476872460 8.
8478692562 Si 6.4613240569 7.1534197148 8.2858208905
Si 9.4995036873 7.7563524417 8.7527939165
O 5.
8289959156 6.1070268707 9.3234506615
O 5.5378138826 8.
4757003887 8.1819820998
O 6.5661104574 6.4615582121 6.
8329636201 O 9.7886737380 9.
3189204480 9.0335420807
&END COORD
&END SUBSYS
&END FORCE_EVAL
&GLOBAL
PROJECT silica
RUN_TYPE ENERGY
PRINT_LEVEL MEDIUM
&END GLOBAL