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# 11.5.8 Calculation of User-Defined EFP Potentials

(July 14, 2022)

User-defined EFP parameters can be generated in MAKEFP job in gamess (see the gamess manual for details). The user-defined parameter (.efp) files should be located in the working directory; the name of the .efp file should match exactly the name of the fragment, for example, beginning of the cl_ion.efp parameter file should look like:

 $cl_ion Comment line COORDINATES (BOHR) ....  The EFP potential generation begins by determining an accurate structure for the fragment (EFP is the frozen-geometry potential, so the fragment geometry will remain the same in all subsequent calculations). We recommend MP2/cc-PVTZ level of theory. ## 11.5.8.1 Generating EFP Parameters Using gamess EFP parameters can be generated in gamess using MAKEFP job (RUNTYP = MAKEFP). For EFP parameters calculations, 6-311++G(3df,2p) basis set is recommended. Originally Stone’s distributed multipole analysis (bigexp = 0 in the group$stone is recommended for non-aromatic compound; optionally, one may decrease the basis set to 6-31G* or 6-31+G* for generation of electrostatic multipoles and screening parameters. (To prepare such a “mixed” potential, one has to run two separate MAKEFP calculations in larger and smaller bases, and combine the corresponding parts of the potential). In aromatic compounds, one must either use numerical grid for generation of multipoles (bigexp = 4.0) or use 6-31G* basis with standard analytic DMA, which is recommended. The MAKEFP job produces (usually in the scratch directory) the .efp file containing all the necessary EFP parameters. See the gamess manual for further details. Below are examples of a gamess input file for RUNTYP = MAKEFP, for water and for benzene.

GAMESS input example for water.

$contrl units=angs local=boys runtyp=makefp coord=cart icut=11$end
$system timlim=99999 mwords=200$end
$scf soscf=.f. diis=.t. conv=1.0d-06$end
$basis gbasis=n311 ngauss=6 npfunc=2 ndfunc=3 nffunc=1 diffs=.t. diffsp=.t.$end
$stone bigexp=0.0$end
$damp ifttyp(1)=3,2 iftfix(1)=1,1 thrsh=500.0$end
$dampgs h3=h2 bo31=bo21$end
$makefp chtr=.f. disp7=.f.$end
$data water h2o (geometry: mp2/cc-pvtz) c1 o1 8.0 0.0000 0.0000 0.1187 h2 1.0 0.0000 0.7532 -0.4749 h3 1.0 0.0000 -0.7532 -0.4749$end

GAMESS input example for benzene.

$contrl units=bohr local=boys runtyp=makefp coord=cart icut=11$end
$system timlim=99999 mwords=200$end
$scf soscf=.f. diis=.t. conv=1.0d-06$end
$basis gbasis=n311 ngauss=6 npfunc=2 ndfunc=3 nffunc=1 diffs=.t. diffsp=.t.$end
$stone bigexp=4.0$end
$damp ifttyp(1)=3,2 iftfix(1)=1,1 thrsh=500.0$end
$dampgs c6=c5 c2=c1 c3=c1 c4=c1 c5=c1 c6=c1 h8=h7 h9=h7 h10=h7 h11=h7 h12=h7 bo32=bo21 bo43=bo21 bo54=bo21 bo61=bo21 bo65=bo21 bo82=bo71 bo93=bo71 bo104=bo71 bo115=bo71 bo126=bo71$end
$makefp chtr=.f. disp7=.f.$end
$data benzene c6h6 (geometry: mp2/cc-pvtz) c1 c1 6.0 1.3168 -2.2807 0.0000 c2 6.0 2.6336 0.0000 0.0000 c3 6.0 1.3168 2.2807 0.0000 c4 6.0 -1.3168 2.2807 0.0000 c5 6.0 -2.6336 -0.0000 0.0000 c6 6.0 -1.3168 -2.2807 0.0000 h7 1.0 2.3386 -4.0506 0.0000 h8 1.0 4.6772 0.0000 0.0000 h9 1.0 2.3386 4.0506 0.0000 h10 1.0 -2.3386 4.0506 0.0000 h11 1.0 -4.6772 0.0000 0.0000 h12 1.0 -2.3386 -4.0506 0.0000$end