Can libefp work with monovalent ions?

Hello,

In the GAMESS MAKEFP documentation, it mentions that if a system contains fewer than three atoms, you can add two dummy atoms with dummy coordinates and multipoles, allowing the MAKEFP calculation to proceed successfully. I’m wondering if there’s a similar feature in the libefp module of QChem for modeling monovalent ions, such as Na+ or Cl-, as effective fragments (EFs) alongside water fragments.

I’ve tried using the following input as suggested in the GAMESS manual, but I’m encountering a segmentation fault (core dumped) error. Has anyone else run into this issue or found a solution?

--------------------------------------------------------------
User input:
--------------------------------------------------------------
$comment
   PDB: so3sq_water-traj1-extract.pdb.10
$end

$molecule
0 1
He	5.0	5.0	5.0
$end

$efp_fragments
na_ion
   A01NA1     18.037001    32.077999    17.301001
   A02He	    5.0          5.0          5.0
   A03He	    5.0          5.0          5.0	
na_ion
   A01NA1     11.189000    15.839000    19.089001
   A02HeHe	    5.0          5.0          5.0
   A03HeH           5.0          5.0          5.0
water_u
   A01O1     27.062000    17.833000     2.781000
   A02H2     27.858000    18.250999     3.111000
   A03H3     26.504000    17.740000     3.553000
water_u
   A01O1     33.230999    16.292999    11.138000
   A02H2     33.622002    16.677999    11.922000
   A03H3     33.470001    15.367000    11.180000
water_u
   A01O1     34.515999    22.712999    21.739000
   A02H2     34.146999    21.872000    21.469000
   A03H3     35.313999    22.802999    21.216999
water_u
   A01O1     23.830999    35.373001     7.635000
   A02H2     23.812000    34.798000     8.401000
   A03H3     23.372000    34.881001     6.955000
$end

$rem
   JOBTYPE           SP
   METHOD            wb97x-d
   BASIS             6-31+G(d)
   BASIS2            STO-3G
   !PURECART          2222
!tddft parameters
   !CIS_N_ROOTS       10
   !CIS_SINGLETS      true
   !CIS_TRIPLETS      false
   !RPA               true
!efp parameters
   EFP               true
   EFP_FRAGMENTS_ONLY   true
   EFP_COORD_XYZ     true
   EFP_DIRECT_POLARIZATION_DRIVER   true
   EFP_EXREP         false
   EFP_DISP          true
   EFP_ELEC_DAMP     1 !Overlap-based damping and 2 for Screen-based damping
   !EFP_DISP_DAMP     1 !TT damping and 2 for Overlap-based damping
   !EFP_POL_DAMP      1
!scf
   THRESH            14
   S2THRESH          16
   MAX_SCF_CYCLES    120
   SCF_CONVERGENCE   8
   !SCF_GUESS         read
   MEM_TOTAL         16000   ! Specify memory in megabytes (16 GB)
$end

Output does not correctly identify Na+ cations.

GEOMETRY OF EFP SUBSYSTEM

    A01NA1       -nan       -nan       -nan
    A01NA1       -nan       -nan       -nan
     A01O1   27.06200   17.83300    2.78100
     A02H2   27.84330   18.24328    3.10491
     A03H3   26.49143   17.72799    3.52066
     A01O1   33.23100   16.29300   11.13800
     A02H2   33.61509   16.67119   11.90814
     A03H3   33.45091   15.37917   11.15338
     A01O1   34.51600   22.71300   21.73900
     A02H2   34.15364   21.88713   21.47386
     A03H3   35.30449   22.82894   21.24049
     A01O1   23.83100   35.37300    7.63500
     A02H2   23.81236   34.80877    8.38665
     A03H3   23.38471   34.91325    6.94715

Following is how the efp parameter file looks like for Na fragment.

 $na_ion
Sodium, All:6-311++G(3df,2p) 5-test_BOYS_CTVVO-FALSE
 COORDINATES (BOHR)
A01NA1     0.0000000000   0.0000000000   0.0000000000  22.9898000 11.0
A02He      0.0000000000   0.0000000000   0.0000000000  0.00000000 0.0
A02He      0.0000000000   0.0000000000   0.0000000000  0.00000000 0.0
 STOP
 MONOPOLES 
A01NA1   -10.0000000000  11.00000
A02He     0.0000000000   0.000000
A02He     0.0000000000   0.000000
 STOP