Figure 1. Example molecule. Highlighted dihedral: C3-C2-C1-O8
obabel -isdf 7jrn_ligand_fragment.sdf -otmol -O fragment.coord
$constrain
force constant=50.0
dihedral: 3,2,1,8,0.0
$scan
1: 0.0,180.0,37
$end
/public/apps/xtb-6.5.1/bin/xtb fragment.coord --opt verytight --input scan.inp --chrg 0 --uhf 0
obabel -ixyz xtbscan.log -osdf -O xtbscan.sdf
extract_result_from_xtbscan.py xtbscan.sdf 3 2 1 8
CONF_ID,Angle,Relative_energy
CONF_1,-0.0024379306925366028,2.5660529817770072
CONF_2,5.008868625895336,2.421691246670976
CONF_3,10.006264798942436,2.093297027544123
CONF_4,15.00388321707389,1.6735896340333944
CONF_5,20.00715882152012,1.2647560229912802
CONF_6,25.000484601098798,0.8956625742899149
CONF_7,30.007529505425715,0.58213106163155
CONF_8,35.004095113856685,0.33556458569846015
CONF_9,40.00801862447416,0.15920944683461613
CONF_10,45.00804589818885,0.05284170597375848
CONF_11,49.99270415026529,0.0
CONF_12,55.00734179011268,0.028588644606113434
CONF_13,60.000498933417326,0.12004189644131635
CONF_14,64.99456640846694,0.2535721908962252
CONF_15,69.99701297899928,0.4036983160734575
CONF_16,74.99655532565676,0.5444593369536221
CONF_17,80.00179918843254,0.673358565949691
CONF_18,85.00122039028727,0.77231599804092
CONF_19,89.9975075815823,0.8223022320087292
CONF_20,95.00738375966014,0.8516286609974788
CONF_21,100.00259993427802,0.8521607966847
CONF_22,104.99847953686145,0.8453869191246799
CONF_23,110.0011877780128,0.806081963800489
CONF_24,115.00441978156354,0.7774579526672376
CONF_25,119.9984682367587,0.77084727154201
CONF_26,125.00170760464812,0.7636051145771461
CONF_27,129.9950398843348,0.8105056405111188
CONF_28,134.99836088974644,0.9126517408357859
CONF_29,139.99480548215223,1.075909500156742
CONF_30,144.99631665389828,1.304110102778182
CONF_31,149.99225955738748,1.6134768207537142
CONF_32,154.99316032897417,1.9901157699614114
CONF_33,159.9907292258415,2.4379784477945154
CONF_34,164.99021865644528,2.9415040766211753
CONF_35,169.98836838604416,3.4729742068748326
CONF_36,174.98865151282774,3.9824196092070707
CONF_37,179.99766277109416,4.283353778243777
Split the conformer ensemble into xyz file:
obabel -ixyz xtbscan.log -oxyz -O CONF_.xyz -m
Split the conformer ensemble into sdf file:
obabel -ixyz xtbscan.xyz -osdf -O CONF_.sdf -m
Create ORCA input file from SDF:
sdf2orca.py CONF_1.sdf 3 2 1 8 CONF_1_opt.inp
Alterantively, create ORCA input file from XYZ:
xyz2orca.py CONF_1.xyz 0 3 2 1 8 CONF_1_opt.inp
cat CONF_1.xyz
22
energy: -31.864953576915 xtb: 6.5.1 (579679a)
C 10.56195 -10.60435 32.85972
C 10.19983 -9.15743 32.99504
C 11.21189 -8.17992 33.00934
C 8.87240 -8.73805 33.10874
C 12.66448 -8.50784 32.89355
C 8.53742 -7.40450 33.23466
C 9.53471 -6.44568 33.25005
O 11.71025 -10.99973 32.75833
C 10.85208 -6.84167 33.13765
N 9.53246 -11.49006 32.85262
C 9.75040 -12.90960 32.73279
H 12.97318 -9.16647 33.70268
H 12.86352 -9.04205 31.96701
H 13.26278 -7.59950 32.92114
H 8.05858 -9.44826 33.10138
H 9.28610 -5.39937 33.34851
H 11.63184 -6.09337 33.14895
H 8.57975 -11.18552 32.94396
H 10.82360 -13.06841 32.63810
H 9.38379 -13.43432 33.61796
H 9.24587 -13.30419 31.84828
H 7.50011 -7.11642 33.32045
cat CONF_1_opt.inp
%PAL NPROCS 24 END
! BP86 DEF2-TZVP D3 OPT RIJCOSX Def2/J
%geom Constraints
{D 2 1 0 7 C}
end
end
* xyzfile 0 1 CONF_1.xyz
orca CONF_1_opt.inp > CONF_1_opt.out
Chemistry model r2scan-3c/def2-mtzvpp and r2scan-3c/def2-tzvp is recommnnded.
Create Gaussian input file from XYZ:
xyz2g16.py CONF_1.xyz 0 3 2 1 8 CONF_1.com
Perform optimization with Gaussian 16 at B3LYP-D3BJ/6-311+G(d,p) level:
g16 -p=24 -m=24GB CONF_1.com
cat CONF_1.com
%chk=CONF_1_D_3-2-1-8_constrained_opt.chk
# B3LYP/6-311+G(d,p) OPT=(modredundant) symmetry=(none) EmpiricalDispersion=(gd3bj)
CONF_1 Dihedral angle 3-2-1-8 constrained optimization
0 1
C 10.56195 -10.60435 32.85972
C 10.19983 -9.15743 32.99504
C 11.21189 -8.17992 33.00934
C 8.87240 -8.73805 33.10874
C 12.66448 -8.50784 32.89355
C 8.53742 -7.40450 33.23466
C 9.53471 -6.44568 33.25005
O 11.71025 -10.99973 32.75833
C 10.85208 -6.84167 33.13765
N 9.53246 -11.49006 32.85262
C 9.75040 -12.90960 32.73279
H 12.97318 -9.16647 33.70268
H 12.86352 -9.04205 31.96701
H 13.26278 -7.59950 32.92114
H 8.05858 -9.44826 33.10138
H 9.28610 -5.39937 33.34851
H 11.63184 -6.09337 33.14895
H 8.57975 -11.18552 32.94396
H 10.82360 -13.06841 32.63810
H 9.38379 -13.43432 33.61796
H 9.24587 -13.30419 31.84828
H 7.50011 -7.11642 33.32045
3 2 1 8 F
!a blank line
Create PSI4 input file from XYZ:
xyz2psi4_dihedral_angle_constrained.py CONF_1.xyz 0 3 2 1 8 > CONF_1.dat
Perform optimization with PSI4 at R2SCAN-3c/DEF2-mTZVPP level:
psi4 -i CONF_1.dat -o CONF_1.out -n 24 --memory 24GB
cat CONF_1.dat
molecule mol{
0 1
C 10.56195 -10.60435 32.85972
C 10.19983 -9.15743 32.99504
C 11.21189 -8.17992 33.00934
C 8.87240 -8.73805 33.10874
C 12.66448 -8.50784 32.89355
C 8.53742 -7.40450 33.23466
C 9.53471 -6.44568 33.25005
O 11.71025 -10.99973 32.75833
C 10.85208 -6.84167 33.13765
N 9.53246 -11.49006 32.85262
C 9.75040 -12.90960 32.73279
H 12.97318 -9.16647 33.70268
H 12.86352 -9.04205 31.96701
H 13.26278 -7.59950 32.92114
H 8.05858 -9.44826 33.10138
H 9.28610 -5.39937 33.34851
H 11.63184 -6.09337 33.14895
H 8.57975 -11.18552 32.94396
H 10.82360 -13.06841 32.63810
H 9.38379 -13.43432 33.61796
H 9.24587 -13.30419 31.84828
H 7.50011 -7.11642 33.32045
}
set optking {
frozen_dihedral = ("
3 2 1 8
")
}
optimize('R2SCAN-3C/DEF2-mTZVPP')
- User Guide to Semiempirical Tight Binding.https://xtb-docs.readthedocs.io/en/latest
- ORCA tutorials. ORCA tutorials - Compatible with ORCA 5.0!
- ORCA input library. https://sites.google.com/site/orcainputlibrary
- M. Bursch, J.-M. Mewes, A. Hansen, S. Grimme. Best-Practice DFT Protocols for Basic Molecular Computational Chemistry. Angew. Chem. Int. Ed. 2022, 61, e202205735. https://doi.org/10.1002/anie.202205735
- Grimme S, Hansen A, Ehlert S, Mewes J-M. r2SCAN-3c: An Efficient “Swiss Army Knife” Composite Electronic-Structure Method. ChemRxiv. 2020; doi:10.26434/chemrxiv.13333520.v2 This content is a preprint and has not been peer-reviewed.
- Thomas Gasevic, Julius B. Stückrath, Stefan Grimme, and Markus Bursch.Optimization of the r2SCAN-3c Composite Electronic-Structure Method for Use with Slater-Type Orbital Basis Sets. The Journal of Physical Chemistry A 2022 126 (23), 3826-3838. DOI: 10.1021/acs.jpca.2c02951