Dear CP2K Users,
I am trying to calculate the RESP charges for a unit cell of the form I crystal of paracetamol using periodic boundary conditions using version 2.5 of CP2K. Â I have tried many different things but in every calculation, the RESP charges seem to be unphysical, i.e. the magnitudes of the charges seem to very large and most have the wrong sign. Â The things I have tried in order to fix this include:
increasing the cutoff
changing the functional
increasing the size of the basis set
changing the values of the LENGTH and RANGE keywords in the PERIODIC_SYS section of RESP
changing the SURF_DIRECTION in the PERIODIC_SYS section of RESP
I've also experimented with the keywords WIDTH, RESTRAIN_HEAVIES_STRENGTH, and RESTRAIN_HEAVIES_TO_ZERO in RESP
Nothing seems to work for the RESP charges. Â However, when I turn off the periodic boundary conditions the calculations produce RESP charges that make physical sense. Â Also, for calculations with or without periodic boundary conditions, the DDAP charges make physical sense, but I'm hesitant to use them in MD simulations since they are less frequently used in MD simulations in the literature. Â If anyone could help identify an error I am making when calculating these RESP charges, I would greatly appreciate it! Â Also, if anyone could comment on the reliability of DDAP charges in general, I would appreciate it as well.
For the calculation, the coordinates of the form I crystal as well as the dimensions of the unit cell were obtained from the cambridge structural database. Â The input file I'm using, the outputted RESP charges, and the outputted DDAP charges are the following:
&GLOBAL
 PROJECT form_1
 RUN_TYPE ENERGY_FORCE
 PRINT_LEVEL MEDIUM
 WALLTIME 86400
&END GLOBAL
&FORCE_EVAL
 METHOD Quickstep
 &DFT
  BASIS_SET_FILE_NAME EMSL_BASIS_SETS
  POTENTIAL_FILE_NAME POTENTIAL
  CHARGE 0
  MULTIPLICITY 1
  &MGRID
   CUTOFF 300
   REL_CUTOFF 50
  &END MGRID
  &QS
   METHOD GAPW
   EPS_DEFAULT  1.0E-12
   MAP_CONSISTENT TRUE
   EXTRAPOLATION ASPC
   EXTRAPOLATION_ORDER 3
  &END QS
  &SCF
   MAX_SCF 500
   SCF_GUESS ATOMIC
   EPS_SCF 1.0E-7
   &OT ON
    MINIMIZER DIIS
    PRECONDITIONER FULL_ALL
    ENERGY_GAP 0.001
   &END OT
   &OUTER_SCF
     EPS_SCF 1.0E-5
     MAX_SCF 100
   &END OUTER_SCF
  &END SCF
  &XC
   &XC_FUNCTIONAL PBE
   &END XC_FUNCTIONAL
  &END XC
 &END DFT
 Â
 &SUBSYS
  &CELL
   ABC 12.93 9.40 7.10
   ALPHA_BETA_GAMMA 90.00 115.90 90.00
   PERIODIC XYZ
  &END CELL
  &COORD
 C     9.510000     3.334000     5.417000
 C     10.770000     3.348000     4.827000
 C     11.771000     2.497000     5.288000
 C     11.518000     1.636000     6.343000
 C     10.266000     1.639000     6.953000
 C     9.279000     2.483000     6.489000
 C     8.231000     4.763000     3.830000
 C     6.944000     5.542000     3.720000
 H     10.930000     3.957000     4.145000
 H     12.675000     2.557000     4.918000
 H     10.101000     1.062000     7.690000
 H     8.407000     2.482000     6.891000
 H     12.348000     0.517000     7.562000
 H     7.724000     4.239000     5.582000
 H     6.614000     5.480000     2.836000
 H     6.512000     5.574000     4.484000
 H     7.181000     6.589000     3.692000
 N     8.426000     4.170000     5.017000
 O     12.536000     0.800000     6.745000
 O     9.035000     4.678000     2.901000
 C     6.784000     8.034000     0.970000
 C     5.524000     8.048000     1.560000
 C     4.523000     7.197000     1.099000
 C     4.776000     6.336000     0.044000
 C     6.028000     6.339000    -0.567000
 C     7.015000     7.183000    -0.102000
 C     8.063000     9.463000     2.557000
 C     9.350000    10.242000     2.667000
 H     5.364000     8.657000     2.242000
 H     3.618000     7.257000     1.469000
 H     6.193000     5.762000    -1.303000
 H     7.887000     7.182000    -0.505000
 H     3.945000     5.217000    -1.175000
 H     8.570000     8.939000     0.805000
 H     9.680000    10.180000     3.551000
 H     9.782000    10.274000     1.903000
 H     9.113000    11.289000     2.695000
 N     7.867000     8.870000     1.370000
 O     3.758000     5.500000    -0.358000
 O     7.259000     9.378000     3.486000
 C     0.319000     6.066000     0.970000
 C     -0.941000     6.052000     1.560000
 C     -1.942000     6.903000     1.099000
 C     -1.689000     7.764000     0.044000
 C     -0.437000     7.761000    -0.567000
 C     0.550000     6.917000    -0.102000
 C     1.598000     4.637000     2.557000
 C     2.885000     3.858000     2.667000
 H     -1.101000     5.443000     2.242000
 H     -2.847000     6.843000     1.469000
 H     -0.272000     8.338000    -1.303000
 H     1.422000     6.918000    -0.505000
 H     -2.520000     8.883000    -1.175000
 H     2.105000     5.161000     0.805000
 H     3.215000     3.920000     3.551000
 H     3.317000     3.826000     1.903000
 H     2.648000     2.811000     2.695000
 N     1.402000     5.230000     1.370000
 O     -2.707000     8.600000    -0.358000
 O     0.794000     4.722000     3.486000
 C     3.045000     1.366000     5.417000
 C     4.305000     1.352000     4.827000
 C     5.306000     2.203000     5.288000
 C     5.053000     3.064000     6.343000
 C     3.801000     3.061000     6.953000
 C     2.814000     2.217000     6.489000
 C     1.766000    -0.063000     3.830000
 C     0.479000    -0.842000     3.720000
 H     4.465000     0.743000     4.145000
 H     6.210000     2.143000     4.918000
 H     3.636000     3.638000     7.690000
 H     1.942000     2.218000     6.891000
 H     5.883000     4.183000     7.562000
 H     1.259000     0.461000     5.582000
 H     0.149000    -0.780000     2.836000
 H     0.047000    -0.874000     4.484000
 H     0.716000    -1.889000     3.692000
 N     1.961000     0.530000     5.017000
 O     6.071000     3.900000     6.745000
 O     2.570000     0.022000     2.901000
  &END COORD
  &KIND H
   BASIS_SET 6-31++Gxx
   POTENTIAL GTH-PBE-q1
  &END KIND
  &KIND C
   BASIS_SET 6-31++Gxx
   POTENTIAL GTH-PBE-q4
  &END KIND
  &KIND N
   BASIS_SET 6-31++Gxx
   POTENTIAL GTH-PBE-q5
  &END KIND
  &KIND O
   BASIS_SET 6-31++Gxx
   POTENTIAL GTH-PBE-q6
  &END KIND
 &END SUBSYS
 &PROPERTIES
  &RESP
   &PERIODIC_SYS
    ATOM_LIST 1..80
LENGTH 3.0
RANGE Â 3.0 5.0
SURF_DIRECTION Z
   &END PERIODIC_SYS
   &PRINT
&V_RESP_CUBE
&END V_RESP_CUBE
&RESP_CHARGES_TO_FILE
&END RESP_CHARGES_TO_FILE
&PROGRAM_RUN_INFO
&END
&COORD_FIT_POINTS
&END
   &END PRINT Â
  &END RESP
  Â
  &FIT_CHARGE
  &END FIT_CHARGE
 &END PROPERTIES Â
&END FORCE_EVAL
RESP charges:
 Type |  Atom  |   Charge
 RESP    1  C   0.070078
 RESP    2  C   0.903292
 RESP    3  C   1.113722
 RESP    4  C   -0.120125
 RESP    5  C   1.058323
 RESP    6  C   0.655164
 RESP    7  C   0.200902
 RESP    8  C   2.666416
 RESP    9  H   -1.222912
 RESP    10  H   -1.170830
 RESP    11  H   -0.983979
 RESP    12  H   -0.818745
 RESP    13  H   -1.214944
 RESP    14  H   -1.366249
 RESP    15  H   -1.224385
 RESP    16  H   -1.119378
 RESP    17  H   -1.137280
 RESP    18  N   1.259042
 RESP    19  O   1.713353
 RESP    20  O   0.738109
 RESP    21  C   0.041413
 RESP    22  C   0.956097
 RESP    23  C   1.040182
 RESP    24  C   -0.082712
 RESP    25  C   1.051482
 RESP    26  C   0.595410
 RESP    27  C   0.202160
 RESP    28  C   2.662283
 RESP    29  H   -1.166123
 RESP    30  H   -1.126516
 RESP    31  H   -0.984189
 RESP    32  H   -0.800838
 RESP    33  H   -1.188989
 RESP    34  H   -1.401436
 RESP    35  H   -1.215709
 RESP    36  H   -1.113423
 RESP    37  H   -1.128041
 RESP    38  N   1.271056
 RESP    39  O   1.679915
 RESP    40  O   0.705805
 RESP    41  C   0.116651
 RESP    42  C   0.813652
 RESP    43  C   1.108160
 RESP    44  C   -0.087035
 RESP    45  C   1.066794
 RESP    46  C   0.598212
 RESP    47  C   0.201601
 RESP    48  C   2.665972
 RESP    49  H   -1.193708
 RESP    50  H   -1.119339
 RESP    51  H   -0.987625
 RESP    52  H   -0.794927
 RESP    53  H   -1.193920
 RESP    54  H   -1.403616
 RESP    55  H   -1.227170
 RESP    56  H   -1.113105
 RESP    57  H   -1.132964
 RESP    58  N   1.272201
 RESP    59  O   1.669491
 RESP    60  O   0.737908
 RESP    61  C   0.017005
 RESP    62  C   0.961044
 RESP    63  C   1.064429
 RESP    64  C   -0.116028
 RESP    65  C   1.044203
 RESP    66  C   0.665757
 RESP    67  C   0.203199
 RESP    68  C   2.660164
 RESP    69  H   -1.159143
 RESP    70  H   -1.166104
 RESP    71  H   -0.983609
 RESP    72  H   -0.830205
 RESP    73  H   -1.208912
 RESP    74  H   -1.380887
 RESP    75  H   -1.210223
 RESP    76  H   -1.114933
 RESP    77  H   -1.129467
 RESP    78  N   1.264612
 RESP    79  O   1.718065
 RESP    80  O   0.706396
 Total        0.000000
 DDAP FULL DENSITY charges:
 Atom   |   Charge
   1  C   0.164768
   2  C   0.038789
   3  C   -0.067304
   4  C   0.359095
   5  C   -0.273509
   6  C   -0.132861
   7  C   0.453357
   8  C   -0.073176
   9  H   -0.008341
  10  H   -0.007149
  11  H   0.160840
  12  H   0.127025
  13  H   0.128967
  14  H   0.094082
  15  H   -0.056650
  16  H   -0.027392
  17  H   -0.004180
  18  N   -0.249484
  19  O   -0.299466
  20  O   -0.327283
  21  C   0.164803
  22  C   0.039171
  23  C   -0.067954
  24  C   0.359126
  25  C   -0.273851
  26  C   -0.132660
  27  C   0.453316
  28  C   -0.072910
  29  H   -0.008512
  30  H   -0.006834
  31  H   0.161121
  32  H   0.126815
  33  H   0.128910
  34  H   0.094007
  35  H   -0.056723
  36  H   -0.027522
  37  H   -0.004288
  38  N   -0.249623
  39  O   -0.299372
  40  O   -0.327146
  41  C   0.164786
  42  C   0.039184
  43  C   -0.067967
  44  C   0.359125
  45  C   -0.273855
  46  C   -0.132651
  47  C   0.453282
  48  C   -0.072882
  49  H   -0.008520
  50  H   -0.006829
  51  H   0.161118
  52  H   0.126809
  53  H   0.128911
  54  H   0.094000
  55  H   -0.056734
  56  H   -0.027529
  57  H   -0.004294
  58  N   -0.249597
  59  O   -0.299364
  60  O   -0.327128
  61  C   0.164787
  62  C   0.038773
  63  C   -0.067297
  64  C   0.359102
  65  C   -0.273505
  66  C   -0.132867
  67  C   0.453392
  68  C   -0.073203
  69  H   -0.008330
  70  H   -0.007154
  71  H   0.160838
  72  H   0.127032
  73  H   0.128964
  74  H   0.094090
  75  H   -0.056640
  76  H   -0.027383
  77  H   -0.004176
  78  N   -0.249513
  79  O   -0.299471
  80  O   -0.327306
 Total    0.000000