Fast and Accurate Generation of ab initio Quality Atomic
Charges using Non-parametric Statistical Regression
Brajesh K. Rai* and Gregory A. Bakken
Computational Sciences CoE, Worldwide MedChem, Pfizer Worldwide Research and Development,
445 Eastern Point Road, Groton, CT 06340, United States
Supplementary Information
Symmetry functions
The
functional
form
of
the
𝐺𝑖𝛼,𝑟𝑎𝑑
radial
and
= ∑∑𝑒
𝛽
angular
𝛼𝛽 2
−𝜏|𝑟⃗𝑖𝑗 |
symmetry
function
are
given
as
𝛼𝛽
𝑓𝑐 (|𝑟⃗𝑖𝑗 |)
𝑗
and
2
𝛼,𝑎𝑛𝑔
𝐺𝑖
2
2
𝛼𝛽
𝛼𝛽
𝛼𝛽
𝑛 −𝜏(|𝑟⃗𝑖𝑗
| +|𝑟⃗𝑗𝑘 | +|𝑟⃗𝑖𝑘 | )
= ∑ ∑(1 ± cos 𝜃𝑖𝑗𝑘 ) 𝑒
𝛽
𝛼𝛽
𝛼𝛽
𝛼𝛽
𝑓𝑐 (|𝑟⃗𝑖𝑗 |) 𝑓𝑐 (|𝑟⃗𝑖𝑘 |) 𝑓𝑐 (|𝑟⃗𝑗𝑘 |)
𝑗,𝑘
𝛼𝛽
𝛽
where 𝛼 and 𝛽 represent chemical elements, 𝑟⃗𝑖𝑗 = 𝑟⃗𝑖𝛼 − 𝑟⃗𝑖 is the vector connecting atoms i and j such
𝛼𝛽
that 𝑟𝑖𝑗 ≤ 𝑟𝑐 , 𝜏 (=0.0001) and 𝑛 (=0.5) determines the shape of the symmetry function and
𝛼𝛽
𝑓𝑐 (|𝑟⃗𝑖𝑗 |)
given as
1
𝛼𝛽
|𝑟⃗𝑖𝑗 |
0.5
×
[cos
(
) + 1]
𝛼𝛽
𝑟𝑐
𝑓𝑐 (|𝑟⃗𝑖𝑗 |) =
{0
𝛼𝛽
𝑓𝑜𝑟 |𝑟⃗𝑖𝑗 | > 𝑟𝑐
𝛼𝛽
𝑓𝑜𝑟 |𝑟⃗𝑖𝑗 | > 𝑟𝑐
Regardless of the type or number of chemical species present, the local environment of each atom is
defined using a vector of fixed length consisting of 126 symmetry function elements (77 radial and 49
angular). Using different cutoff radius, 𝑟𝑐 , ranging from 1.0 Å to 6.0 Å and with 0.5 Å increment, 77
radial symmetry function elements are defined. The first 77 elements of the vector represent positions of
all neighbors of a given atom type within the specified distance cutoff. For example, the first 11
elements of the vector represent the radial distribution of hydrogen atoms at distances ranging from 1.0
Å to 6.0 Å, the next 11 elements represent positions of carbon atoms, and so on. For the angular
symmetry function, we use a single cutoff radius (rc = 3.0 Å), which results in 49 elements.
It should be noted that the choice of limiting cutoff radius, 𝑟𝑐 , to 6.0 Å for radial symmetry functions
and to 3.0 Å for angular symmetry functions was done primarily to reduce the computational
complexity of the model building process and the runtime memory footprint of these models. We realize
that these cutoffs introduce an approximation in the treatment of the long-range interactions, and, thus,
could potentially lead to underperformance on systems comprised of molecules with formal charges and
zwitterions. However, on our test set, we have found that increasing the cutoff radius beyond the
existing thresholds provides little improvement in model performance.
Refinement of QM ESP-fit charges
Refined charges are obtained by minimizing χ2 (Eq. 6 in the main text), which is obtained by solving
the system of equations:
2
𝑀
𝑁
𝑞𝑗
∂χ2
2
= 0 = − ∑ (𝑉𝑖𝑄𝑀 − ∑ ) − 2𝐶𝜎𝑘′ (𝑞𝑘𝑝𝑟𝑒 − 𝑞𝑘 ) + 𝜆, for all k
∂q k
𝑟𝑖𝑘
𝑟𝑖𝑗
𝑖=1
(1)
𝑗=1
and
𝑁
∂χ2
= 0 = ∑ 𝑞𝑗 − 𝑄 𝑛𝑒𝑡
∂λ
(2)
𝑗=1
Eq 8 and 9 can be rearranged as
𝑀
𝑁
𝑀
𝑞𝑗
𝑉𝑖
∑∑
+ 𝐶𝜎𝑘′ 𝑞𝑘 = ∑ + 𝐶𝜎𝑘′ 𝑞𝑘𝑝𝑟𝑒 + 𝜆
𝑟𝑖𝑗 𝑟𝑖𝑘
𝑟𝑖𝑘
𝑖=1 𝑗=1
(3)
𝑖=1
and
𝑁
∑ 𝑞𝑗 = 𝑄 𝑛𝑒𝑡
(4)
𝑗=1
Equation 10 can be further simplified as
𝑁
∑ 𝐴𝑗𝑘 𝑞𝑗 + 𝐶𝜎𝑘′ 𝑞𝑘 = 𝐵𝑘 + 𝜆
(5)
𝑗=1
where
𝑀
𝐴𝑗𝑘 = ∑
𝑖=1
1
𝑟𝑖𝑗 𝑟𝑖𝑘
(6)
and
𝑀
𝑉𝑖𝑄𝑀
𝐵𝑘 = ∑
+ 𝐶𝜎𝑘′ 𝑞𝑘𝑝𝑟𝑒
𝑟𝑖𝑘
(7)
𝑖=1
The system of linear equation, as described by Eq. 4 and 5 can be written in matrix form as
𝐴11 + 𝐶𝜎1′
𝐴21
.
.
𝐴𝑛1
[
1
𝐴12
𝐴22 + 𝐶𝜎2′
.
.
𝐴𝑛2
1
⋯
…
⋱
.
.
1
𝐴1𝑛
𝐴2𝑛
.
.
𝐴𝑛𝑛 + 𝐶𝜎𝑛′
1
1
1
1
1
1
0]
𝑞1
𝑞2
.
.
𝑞𝑛
[𝜆]
(8)
3
As described in the main text, Eq. 8 can be solved to obtained refined charges.
Training and Test Set
Models were built using QM data from nearly 80,000 molecules that were randomly selected from the
Pfizer corporate library and the publicly available ZINC database (ZINC is a collection of over 14
million commercially available compounds, which is used routinely for virtual screening to identify
potential drug-like molecules). The method is tested using another large, independent test set of 5000
molecules, which were also randomly selected from the Pfizer and ZINC databases. The training and
test set consisted of neutral (90% of the dataset) and charged (10% of the dataset) molecules. The
datasets were represented by roughly equal number of molecules from Pfizer and ZINC databases, but
were restricted to include only those molecules that comprised of H, C, N, O, F, S, or Cl atoms.
Furthermore, to generate the required QM data using a reasonable amount of CPU time and compute
resources, the total number of atoms in the training and test molecules was limited to 100. With such
large-scale sampling, we ensure an extensive coverage of the synthetically available organic chemical
space, and the applicability of the resulting models to pharmaceutically relevant molecules. Indeed,
these molecules cover a wide range of physicochemical properties, reflecting the rich chemical diversity
of these databases, as illustrated in Fig. 1, which shows the distribution of key classical (molecular
weight, polar surface area, logP, number of rotatable bonds, and N and O atom counts) and quantum
mechanical (minimum and maximum ESP on molecular surface and dipole moment) properties of the
training and test molecules.
4
Figure 1. Distribution of key physicochemical and quantum mechanical properties of the training and
test set.
5
Atomic Charges
Figure 2. Atomic charges on different atoms from the test set molecules using ESP-fit charges derived
at the b3lyp/6-31G* level of theory versus the charges from PCAM: Hydrogen (A); Carbon (B);
Nitrogen (C); Oxygen (D); Fluorine (E); Sulfur (F); Chlorine (G). The x-axis and y-axis of each subplot
correspond to ESP-fit and PCAM charges, respectively.
6
Figure 3. Three-dimensional structure and atom-numbering scheme of Tadalafil.
Table 1: Atomic charges on Tadalafil using PCAM, AM1-BCC, OPLS-2005, MMFF, and Gasteiger
charge models. All charges were calculated using a Corina-generated structure. ESP-fit charges were
generated by fitting to QM electrostatic potentials. Atomic index and atom name correspond to the
illustration in Fig. 2.
Index
Atom name
ESP-fit
PCAM
1
2
3
4
5
C1
C2
C3
C4
C5
-0.18
-0.09
-0.29
0.27
0.01
-0.18
-0.09
-0.30
0.28
-0.01
AM1BCC
-0.15
-0.11
-0.14
0.09
-0.08
OPLS-2005
MMFF
Gasteiger
-0.12
-0.12
-0.12
0.13
-0.05
-0.15
-0.15
-0.15
-0.15
0.00
-0.06
-0.06
-0.04
0.04
0.00
7
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
C6
N7
C8
C9
C10
N11
C12
C13
C14
C15
N16
C17
C18
C19
C20
C21
C22
C23
O24
C25
O26
O27
O28
C29
H30
H31
H32
H33
H34
H35
H36
H37
H38
H39
H40
H41
H42
H43
H44
H45
H46
H47
H48
Mean Abs Deviation
from QM ESP-fit charges
-0.14
-0.49
0.14
-0.15
-0.03
-0.18
-0.13
-0.01
0.60
-0.45
0.10
0.38
0.17
-0.23
-0.28
0.25
0.35
-0.44
-0.35
0.27
-0.37
-0.55
-0.52
-0.36
0.12
0.11
0.15
0.13
0.36
0.13
0.15
0.08
0.06
0.18
0.17
0.14
0.18
0.19
0.11
0.04
0.14
0.14
0.14
-0.15
-0.49
0.10
-0.10
-0.03
-0.13
-0.07
-0.07
0.59
-0.37
-0.05
0.42
0.10
-0.17
-0.30
0.27
0.33
-0.39
-0.36
0.26
-0.36
-0.55
-0.54
-0.27
0.12
0.11
0.15
0.13
0.37
0.13
0.11
0.09
0.07
0.16
0.16
0.11
0.18
0.18
0.10
0.05
0.12
0.13
0.13
0.01
-0.08
-0.56
0.03
-0.13
0.22
-0.47
0.03
-0.02
0.70
0.03
-0.48
0.69
-0.09
-0.12
-0.11
0.06
0.06
-0.12
-0.33
0.32
-0.34
-0.63
-0.63
0.09
0.13
0.13
0.13
0.14
0.45
0.11
0.10
0.08
0.06
0.08
0.08
0.14
0.16
0.15
0.08
0.07
0.05
0.05
0.05
0.11
-0.12
-0.57
-0.12
0.08
0.24
-0.14
0.01
-0.12
0.50
-0.05
-0.14
0.50
-0.12
-0.12
-0.12
0.09
0.09
-0.12
-0.28
0.20
-0.28
-0.50
-0.50
-0.11
0.12
0.12
0.12
0.12
0.42
0.06
0.06
0.06
0.06
0.06
0.06
0.12
0.12
0.12
0.10
0.10
0.06
0.06
0.06
0.14
-0.15
0.03
-0.33
-0.18
0.62
-0.66
0.36
0.18
0.57
0.36
-0.66
0.57
-0.14
-0.15
-0.15
0.08
0.08
-0.15
-0.36
0.56
-0.36
-0.57
-0.57
0.30
0.15
0.15
0.15
0.15
0.27
0.00
0.00
0.00
0.00
0.00
0.00
0.15
0.15
0.15
0.00
0.00
0.00
0.00
0.00
0.17
-0.05
-0.32
0.04
-0.02
0.09
-0.28
0.11
0.00
0.23
0.09
-0.29
0.24
-0.02
-0.05
-0.03
0.11
0.11
-0.02
-0.32
0.16
-0.32
-0.27
-0.27
0.00
0.06
0.06
0.06
0.06
0.15
0.06
0.06
0.03
0.03
0.06
0.06
0.06
0.06
0.06
0.09
0.09
0.04
0.04
0.04
0.21
8
Hydration Free Energy
Table 2: Experimental and computed free energies of hydration in kcal/mol.
Name
PCAM
OPLS2005
OPLS-2005 (Ref
44)
MMFF
Gasteiger
-4.72
-4.11
-4.43
-3.34
-5.10
-3.95
-4.12
-0.75
1-Hexyne, ID: C693027
0.29
-1.45
-1.44
0.03
-0.05
1.58
-0.24
0.60
chloro-difluoro-methane CHClF2
-0.50
0.05
-0.92
-1.70
-7.47
0.81
-3.86
-0.46
1-Hexanol, ID: C111273
-4.36
-4.12
-4.24
-3.09
-4.88
-3.39
-3.79
-0.46
Butanenitrile, ID: C109740
-2.96
-2.62
-1.94
-3.78
-3.09
-5.26
0.47
1-methyl-1H-pyridin-2-one C6H7NO
-3.64
10.00
-8.18
-7.74
-10.40
-4.44
-5.91
-9.47
-2.60
Pentanal, ID: C110623
-3.44
-3.11
-3.11
-4.50
-3.28
-1.60
-7.29
-1.63
formic acid methyl ester C2H4O2
-2.78
-7.37
-7.57
-8.95
-6.63
-3.46
-11.45
-5.63
Phenanthrene, ID: C85018
-3.95
-3.41
-3.93
-6.00
-4.09
-2.81
-6.91
-1.39
Acetic acid, methyl ester, ID: C79209
-3.32
-5.55
-6.00
-6.80
-3.20
-1.54
-5.88
-2.52
2.59
1.85
1.89
2.69
2.44
2.51
2.94
2.81
2,2,2-trifluoroethanol C2H3F3O
-4.31
-3.62
-3.45
-4.74
-5.45
-3.81
-6.07
-1.42
2-methoxyethanamine C3H9NO
2-chloro-2-(difluoromethoxy)-1,1,1-trifluoro-ethane
C3H2ClF5O
-6.55
-5.96
-7.00
-7.04
-6.73
-4.84
-8.74
-4.24
0.11
0.20
-0.18
-2.27
-1.16
0.59
-4.81
-0.09
2.50
1.79
1.97
2.62
2.32
2.32
2.89
2.76
Acetaldehyde, ID: C75070
-3.50
-3.37
-3.88
-5.38
-3.84
-2.10
-8.16
-2.29
Methyl propyl ether, ID: C557175
-1.59
-1.78
-1.51
-1.87
-1.57
-0.34
-3.64
-1.88
Butanal, ID: C123728
-3.18
-3.19
-3.29
-4.68
-3.37
-1.80
-7.47
-1.78
Methane, ID: C74828
2.00
0.53
0.76
0.91
0.83
2.20
0.92
0.91
Methyl alcohol, ID: C67561
-5.11
-4.50
-5.73
-4.16
-5.80
-4.33
-5.18
-1.51
Phenol, 4-methyl-, ID: C106445
Propane, 2,2-dimethyl-, ID: C463821
ESP-fit
AM1BCC
1-Butanol, ID: C71363
Butane, 2,2-dimethyl-, ID: C75832
Expt.
-6.14
-4.46
-4.84
-6.04
-6.16
-5.40
-7.45
-1.51
2-Pentene, (Z)-, ID: C627203
1.34
1.02
1.17
1.50
1.41
2.31
0.92
2.03
Ethylene, ID: C74851
1.27
0.34
-0.01
0.97
0.89
1.95
0.38
1.47
1-Hexene, ID: C592416
1.68
0.93
0.78
1.63
1.41
2.83
1.14
2.14
2,6-dimethylpyridine C7H9N
-4.60
-2.32
-2.26
-3.28
-5.22
-4.87
-6.58
0.19
1,1,2-trichloroethane C2H3Cl3
-1.95
-2.79
-1.10
-2.49
-4.22
0.45
-10.09
-0.93
Propyne, ID: C74997
-0.31
-1.73
-1.50
-0.56
-0.29
0.97
-0.86
0.07
1.58
1.75
1.78
1.84
1.54
1.71
2.11
1.97
Cyclohexane, 1,2-dimethyl-, cis-, ID: C2207014
p-Xylene, ID: C106423
-0.81
0.70
0.61
-0.42
-0.97
-1.33
-1.93
1.75
Ethane, 1,1,1-trichloro-, ID: C71556
-0.25
-0.09
0.36
-0.20
-0.68
0.97
-7.47
0.74
Propanoic acid, ethyl ester, ID: C105373
-2.80
-4.58
-4.49
-5.38
-2.23
-1.07
-4.41
-1.52
Methyl fluoride, ID: C593533
0.73
0.15
-0.83
0.07
-0.33
0.47
-0.84
-0.26
methylsulfanylbenzene C7H8S
-2.73
-2.78
-3.17
-2.99
-3.08
-1.22
-4.57
-0.28
Toluene, ID: C108883
-0.89
-0.15
-0.44
-1.12
-1.03
-0.74
-2.37
1.16
2.38
1.60
1.77
2.20
1.94
2.63
2.39
2.30
2,4-dimethylpyridine C7H9N
-4.86
-3.46
-4.32
-4.12
-5.57
-4.24
-7.65
-0.42
1-methyl-2-nitro-benzene C7H7NO2
-3.59
-4.72
-4.58
-3.21
-3.59
-2.55
-8.28
-8.30
1,4-dichlorobenzene C6H4Cl2
-1.01
-1.18
-1.68
-1.84
-1.50
-0.63
-1.96
-0.21
Ethanol, 1,1-dimethyl-, ID: C75650
-4.51
-2.12
-2.49
-1.69
-2.88
-4.18
-2.27
0.34
3-hydroxybenzonitrile C7H5NO
-9.67
-8.40
-8.37
-8.98
-8.52
-6.98
-11.30
-3.13
N,N-diethylethanamine C6H15N
-4.07
-0.23
-0.62
-3.62
-3.40
-1.07
-3.22
0.78
Butane, 2-methyl-, ID: C78784
9
1-Pentyne, ID: C627190
0.01
-1.58
-1.18
-0.10
-0.14
1.19
-0.40
0.46
1-Propanol, ID: C71238
-4.67
-4.38
-4.09
-3.49
-5.13
-4.39
-4.29
-0.90
1-Pentene, ID: C109671
1.66
0.83
0.78
1.49
1.31
2.42
0.98
1.99
Benzene, methoxy-, ID: C100663
-3.73
-3.31
-3.56
-4.65
-3.15
-0.72
-5.63
-2.94
1-nitrobutane C4H9NO2
-3.08
-6.60
-6.81
-2.12
-6.01
-2.63
-12.12
-13.04
Ethane, 1,2-dimethoxy-, ID: C110714
-3.86
-4.38
-4.50
-6.15
-5.82
-3.06
-10.42
-6.68
2-methylpyridine C6H7N
-4.63
-3.77
-4.09
-4.74
-5.22
-3.71
-8.09
-1.04
Isopropyl alcohol, ID: C67630
-4.76
-3.96
-4.41
-3.70
-5.40
-4.15
-4.49
-0.98
1-Butene, ID: C106989
1.38
0.88
1.08
1.34
1.22
2.25
0.81
1.84
Formic acid, ethyl ester, ID: C109944
-2.65
-6.71
-8.69
-8.26
-6.08
-1.07
-10.88
-5.13
Ethylbenzene, ID: C100414
-0.80
0.18
-0.34
-0.83
-0.70
-0.46
-2.02
1.32
Ethanol, ID: C64175
-5.01
-3.63
-4.73
-3.70
-5.47
-4.45
-4.48
-1.12
Pentane, 2-methyl-, ID: C107835
2.52
1.85
1.74
2.38
2.08
2.92
2.59
2.49
Ethene, tetrafluoro-, ID: C116143
1.38
2.39
2.29
1.92
2.03
2.76
1.67
1.35
N-methylformamide C2H5NO
-10.0
-9.86
-11.28
-12.45
-10.26
-6.63
-13.45
-5.75
Ethylamine, ID: C75047
-4.50
-4.24
-4.84
-3.80
-4.29
-2.94
-4.33
-0.73
1,3-Butadiene, ID: C106990
0.60
-0.01
-0.25
0.50
0.61
1.43
-0.27
1.54
1-propylsulfanylpropane C6H14S
-1.27
-2.07
-1.95
-0.21
-0.42
0.46
-1.38
1.72
Fluorene, ID: C86737
-3.44
-2.40
-2.45
-4.91
-3.74
-2.73
-5.86
-0.53
2.85
2.19
2.19
2.99
2.69
2.87
3.25
3.12
-4.23
-3.58
-3.83
-6.21
-4.32
-3.04
-7.10
-1.64
2.33
1.98
1.77
2.19
1.88
2.48
2.38
2.29
-3.66
-2.48
-2.03
-1.86
-2.23
-1.83
-2.29
1.17
1.27
0.59
0.28
1.17
1.12
1.74
0.53
1.70
2,5-dimethylpyridine C7H9N
-4.72
-2.88
-3.76
-3.67
-5.22
-4.42
-7.15
-0.24
1-phenylethanone C8H8O
-4.58
-3.79
-3.98
-6.29
-4.13
-3.44
-8.10
-1.21
2.89
2.17
2.18
2.57
2.16
3.55
2.84
2.72
Cyclopentanol, ID: C96413
-5.49
-4.07
-4.83
-4.08
-5.81
-4.72
-4.66
-1.33
Benzene, 1,2-dimethyl-, ID: C95476
-0.90
0.50
0.49
-0.62
-1.20
-1.54
-2.12
1.57
1.20
1.11
0.78
0.92
0.51
1.93
1.24
1.10
-1.43
-0.65
-1.07
-1.60
-2.57
-1.28
-2.19
0.96
0.04
-1.84
-2.66
-1.47
-0.87
0.57
-1.26
0.02
Pentane, 2,2,4-trimethyl-, ID: C540841
Anthracene, ID: C120127
Pentane, ID: C109660
N-propylpropan-1-amine C6H15N
Propene, ID: C115071
Octane, ID: C111659
Cyclopentane, ID: C287923
diethyldisulfide C4H10S2
1-Buten-3-yne, ID: C689974
Cyclopropane, ID: C75194
0.75
-1.34
-0.74
0.51
0.63
2.18
-0.07
0.95
-0.16
-1.36
-1.24
-0.29
-0.23
1.13
-0.58
0.28
2-chloro-1,1,1-trifluoro-ethane C2H2ClF3
0.06
-0.10
-0.25
-0.99
-1.25
0.59
-4.52
-0.12
Butane, ID: C106978
2.08
1.54
1.79
2.07
1.79
2.54
2.22
2.15
Acetamide, ID: C60355
-9.71
-9.71
-9.56
-11.02
-10.05
-8.47
-11.01
-2.60
Trichloroethylene, ID: C79016
-0.39
-0.08
-0.86
-0.50
-0.44
0.29
-1.95
-0.10
morpholine C4H9NO
-7.17
-6.71
-7.32
-8.31
-7.90
-5.54
-9.29
-4.31
Methylamine, ID: C74895
-4.56
-4.67
-5.47
-4.19
-4.56
-2.98
-4.77
-0.68
1-Butyne, ID: C107006
Propane, ID: C74986
1.96
1.67
1.45
1.94
1.68
2.42
2.06
2.00
nitrobenzene C6H5NO2
-4.12
-5.70
-5.66
-3.97
-4.63
-2.61
-9.89
-9.88
Acetic acid, 1-methylethyl ester, ID: C108214
-2.65
-4.48
-4.69
-5.66
-2.21
-0.99
-4.62
-1.57
1,3-Dioxolane, ID: C646060
-4.10
-5.89
-6.31
-7.81
-6.57
-2.50
-9.27
-5.83
2-methylpyrazine C5H6N2
-5.57
-5.70
-6.54
-8.62
-6.31
-3.33
-13.69
-3.32
Acetone, ID: C67641
-3.85
-3.70
-3.27
-4.94
-3.57
-2.64
-6.82
-1.46
4-methylmorpholine C5H11NO
-6.34
-4.93
-4.74
-9.38
-7.88
-4.21
-9.54
-4.10
10
Acetonitrile, ID: C75058
-3.89
-3.29
-2.70
-2.83
-4.63
-3.70
-6.14
-0.09
hydrogen sulfide H2S
-0.70
-3.19
-2.43
-3.87
-2.09
1.01
-2.70
-1.03
Benzaldehyde, 3-hydroxy-, ID: C100834
-9.51
-8.47
-8.57
-11.43
-9.76
-7.94
-14.39
-4.74
1-Propanamine, ID: C107108
-4.39
-4.62
-4.60
-3.53
-4.03
-2.63
-4.08
-0.54
Propane, 2-methoxy-2-methyl-, ID: C1634044
-0.79
-0.76
-0.95
-1.08
-0.84
-0.44
-2.09
-0.94
1-methylpiperazine C5H12N2
-7.77
-5.91
-6.15
-10.87
-10.53
-6.99
-10.19
-2.51
1,2-dichlorobenzene C6H4Cl2
-1.36
-1.16
-1.89
-2.00
-1.72
-0.64
-2.34
-0.07
Benzene, ID: C71432
-0.87
-0.76
-1.65
-1.80
-1.13
-0.06
-2.82
0.57
N,N-dimethylacetamide C4H9NO
-8.50
-9.71
-10.21
-12.15
-8.36
-7.31
-13.02
-6.60
3-nitrophenol C6H5NO3
-9.63
-10.19
-10.20
-8.58
-10.25
-7.61
-15.38
-12.89
2-Pentanone, ID: C107879
-3.41
-2.86
-2.49
-3.79
-2.94
-2.47
-5.68
-0.82
Ethene, 1,2-dichloro-, (Z)-, ID: C156592
-1.17
-1.20
-1.82
-1.61
-1.46
-0.12
-2.69
-0.26
1-Heptanol, ID: C111706
-4.42
-3.94
-4.02
-2.95
-4.78
-3.26
-3.63
-0.32
Ethene, chloro-, ID: C75014
-0.59
-0.38
-0.72
-0.28
0.17
1.20
-0.45
0.77
Dimethyl sulfide, ID: C75183
-1.54
-2.05
-1.79
-1.14
-1.98
-0.62
-3.08
0.61
1-Butanamine, ID: C109739
-4.29
-4.22
-4.85
-3.38
-3.96
-2.52
-3.92
-0.40
nitroethane C2H5NO2
-3.71
-6.46
-6.71
-2.66
-6.41
-2.75
-12.73
-14.40
0.56
0.61
0.20
-0.01
0.01
1.27
-0.27
0.90
Propane, 2-methoxy-, ID: C598538
-1.31
-1.39
-1.59
-1.77
-1.47
-0.46
-3.20
-1.70
Propane, 2-chloro-, ID: C75296
-0.25
0.27
0.90
0.40
0.35
1.02
-0.71
1.24
1-Propanethiol, ID: C107039
-1.05
-3.23
-2.23
-1.97
-1.44
-0.06
-2.15
0.15
1,4-Dioxane, ID: C123911
-6.69
-5.53
-5.82
-6.95
-5.04
-2.60
-8.65
-5.61
chloro-fluoro-methane CH2ClF
-0.77
-1.18
-2.06
-1.84
-1.72
0.10
-3.63
-0.91
2,2,2-trifluoroethoxyethylene C4H5F3O
-0.12
-0.56
-1.13
-2.11
-2.14
-0.01
-4.12
-1.01
Acetylene, ID: C74862
-0.01
-3.32
-3.82
-1.48
-2.08
1.19
-1.71
-1.02
Ethane, 1,1-difluoro-, ID: C75376
-0.11
0.50
0.44
-0.27
0.42
1.29
-1.46
-0.16
Furan, tetrahydro-, ID: C109999
-3.84
-2.84
-2.95
-3.78
-3.20
-1.47
-5.17
-3.32
Piperidine, ID: C110894
-5.11
-3.41
-3.48
-3.58
-4.08
-3.36
-4.02
-0.60
Benzaldehyde, ID: C100527
-4.02
-4.00
-4.40
-6.80
-4.53
-2.97
-9.22
-2.00
Naphthalene, 2,7-dimethyl-, ID: C582161
-2.63
-0.67
-0.81
-2.63
-2.48
-2.45
-4.02
0.60
2-Butanone, ID: C78933
-3.64
-2.83
-3.24
-3.74
-3.05
-2.31
-5.75
-0.98
n-Propyl acetate, ID: C109604
-2.86
-5.95
-5.66
-6.15
-2.55
-1.04
-5.20
-1.85
2-nitropropane C3H7NO2
-3.14
-5.78
-5.63
-1.90
-5.06
-2.30
-11.28
-11.68
1.34
1.41
1.38
1.66
1.66
2.30
1.02
2.14
propiononitrile C3H5N
-3.85
-2.90
-1.94
-2.22
-3.98
-3.39
-5.50
0.26
benzonitrile C7H5N
-4.10
-4.10
-3.78
-4.17
-3.07
-2.30
-5.97
-0.34
Ethanol, 2-methoxy-, ID: C109864
-6.77
-7.04
-7.48
-9.03
-9.83
-4.95
-11.17
-5.61
Methanamine, N-methyl-, ID: C124403
-4.56
-2.64
-2.55
-3.42
-3.88
-2.47
-3.95
0.52
2-Propen-1-ol, ID: C107186
-5.08
-4.51
-4.82
-4.32
-5.73
-4.55
-5.71
-1.21
Benzene, 1,3-dimethyl-, ID: C108383
-0.84
0.56
0.41
-0.42
-0.98
-1.06
-1.93
1.75
Cyclopentene, ID: C142290
2-Pentene, (E)-, ID: C646048
Pentane, 2,4-dimethyl-, ID: C108087
2.88
1.78
1.87
2.55
2.24
2.95
2.78
2.66
Propane, 1-chloro-, ID: C540545
-0.27
-0.44
-0.16
0.29
-0.03
0.96
-0.90
1.10
aniline C6H7N
-5.50
-4.84
-4.83
-5.50
-3.45
-3.60
-6.09
-0.37
1.27
1.15
1.34
1.59
1.75
2.05
0.78
2.16
-2.92
-1.71
-2.47
-2.12
-1.84
-1.14
-3.21
-1.84
0.10
0.44
0.69
-0.03
-5.70
0.25
-13.17
0.33
-4.70
-5.12
-6.71
-6.24
-5.36
-2.68
-9.61
-2.26
1-Propene, 2-methyl-, ID: C115117
cis 2,5-dimethyltetrahydrofuran C6H12O
Carbon tetrachloride, ID: C56235
Pyridine, ID: C110861
11
Octanal, ID: C124130
-2.29
-2.76
-2.56
-4.14
-3.02
-1.21
-6.80
-1.21
Ethoxy ethane, ID: C60297
-2.64
-0.61
-0.93
-1.64
-1.38
-0.48
-3.10
-1.60
Acenaphthylene, ID: C208968
-3.15
-3.58
-3.88
-6.84
-3.81
-2.11
-5.81
-1.65
azetidine C3H7N
-5.56
-3.80
-5.03
-5.36
-5.78
-3.45
-4.56
-1.33
Ethanethiol, ID: C75081
-1.30
-2.31
-2.10
-2.26
-1.69
-0.29
-2.36
-0.02
1-Pentanol, ID: C71410
-4.47
-3.77
-4.68
-3.21
-4.97
-3.59
-3.95
-0.60
acetic acid pentyl ester C7H14O2
-2.45
-5.37
-5.48
-5.81
-2.38
-0.50
-4.85
-1.55
Methanethiol, ID: C74931
-1.24
-3.10
-3.24
-2.70
-2.19
-0.51
-2.91
-0.36
Phenol, ID: C108952
-6.62
-5.18
-5.71
-6.79
-6.37
-4.64
-7.96
-2.14
5-nonanone C9H18O
-2.67
-2.34
-1.84
-2.45
-2.23
-1.75
-4.17
0.09
benzoic acid methyl ester C8H8O2
-4.90
-5.14
-7.75
-3.70
-2.44
-6.96
-1.67
4-methyl-1H-imidazole C4H6N2
-4.28
10.25
-9.00
-9.91
-9.96
-10.82
-8.50
-14.17
-2.50
1-Octanol, ID: C111875
-4.09
-3.58
-3.80
-2.82
-4.69
-3.23
-3.47
-0.17
Ethyl acetate, ID: C141786
-3.10
-5.33
-5.24
-6.40
-2.78
-3.47
-5.43
-2.07
Dimethyl ether, ID: C115106
-2.64
-1.94
-1.14
-2.58
-2.20
-0.75
-4.59
-2.62
chlorobenzene C6H5Cl
-1.12
-1.06
-1.43
-1.86
-0.97
0.29
-1.98
0.24
Propanal, ID: C123386
-3.44
-3.32
-3.00
-4.94
-3.45
-2.11
-7.65
-1.95
N-ethylethanamine C4H11N
-4.50
-1.27
-1.77
-2.50
-2.78
-2.45
-2.79
0.76
2.49
1.96
1.78
2.32
1.97
2.83
2.53
2.43
Octanoic acid, methyl ester, ID: C111115
-2.04
-4.65
-4.27
-5.19
-2.20
-0.10
-4.07
-1.20
Methylene chloride, ID: C75092
-1.36
-1.63
-0.97
-1.57
-2.09
-0.37
-5.71
-0.33
3,3-dimethylbutan-2-one C6H12O
-2.89
-2.10
-1.79
-2.45
-1.59
-2.05
-4.01
0.16
4-methylpyridine C6H7N
-4.94
-4.97
-5.13
-5.61
-5.51
-2.97
-9.14
-1.64
pentanoic acid methyl ester C6H12O2
-2.57
-4.86
-4.82
-5.47
-2.49
-0.73
-4.55
-1.62
1.23
1.24
1.27
1.06
0.66
1.64
1.34
1.20
Hexane, ID: C110543
Cyclohexane, ID: C110827
benzenethiol C6H6S
-2.55
-3.12
-3.66
-4.80
-2.88
-0.75
-4.33
-1.30
Heptane, ID: C142825
2.62
1.83
1.92
2.45
2.07
2.88
2.69
2.57
2-hexanone C6H12O
-3.29
-2.90
-2.66
-3.63
-2.89
-1.90
-5.47
-0.68
Ethyl chloride, ID: C75003
-0.63
-0.12
-0.11
0.01
-0.35
0.56
-1.19
0.87
4-Heptanone, ID: C123193
-2.93
-2.14
-1.56
-2.89
-2.32
-2.38
-4.58
-0.20
1.71
1.28
1.30
1.50
1.12
1.65
1.80
1.65
1-pentanamine C5H13N
-4.10
-4.16
-4.32
-3.27
-3.84
-2.41
-3.75
-0.25
Chloroform, ID: C67663
-1.07
-0.83
0.05
-1.32
-1.09
0.20
-9.61
-0.27
Propanamide, ID: C79050
-9.41
-8.29
-8.74
-9.53
-9.52
-8.24
-10.05
-2.16
3-methylpyridine C6H7N
-4.77
-4.44
-5.12
-5.19
-5.24
-2.87
-8.65
-1.47
1.23
-2.14
0.77
-0.02
1.27
0.92
-19.13
-0.21
Hexanoic acid, methyl ester, ID: C106707
-2.49
-4.41
-5.02
-5.27
-2.39
-0.55
-4.40
-1.48
Disulfide, dimethyl, ID: C624920
-1.54
-1.76
-3.47
-2.15
-3.94
-1.80
-3.31
0.21
2-methylphenol C7H8O
-5.87
-4.10
-4.25
-5.59
-5.51
-4.73
-6.97
-1.20
Naphthalene, 1,3-dimethyl-, ID: C575417
-2.47
-0.74
-0.82
-2.66
-2.61
-2.36
-4.08
0.53
Tetrachloroethylene, ID: C127184
0.05
0.72
0.68
0.60
0.26
0.85
-1.80
0.13
1,4-dimethylpiperazine C6H14N2
-3.72
-3.90
-11.77
-10.56
-5.29
-10.58
-2.45
N-methylacetamide C3H7NO
-7.58
10.00
-9.31
-10.14
-11.61
-9.33
-8.47
-11.87
-4.52
3-chloroprop-1-ene C3H5Cl
-0.57
-0.82
-0.90
-0.34
-0.59
0.37
-1.90
0.81
0.05
0.72
0.68
0.60
0.26
0.76
-1.80
0.13
-7.40
-8.20
-8.33
-9.89
-10.25
-7.63
-9.53
-2.53
Cyclohexane, methyl-, ID: C108872
1,1,1,2,2,2-hexachloroethane C2Cl6
1,1,2,2-tetrachloroethylene C2Cl4
piperazine C4H10N2
12
Methyl chloride, ID: C74873
-0.56
-0.80
-0.10
-0.25
-0.86
0.23
-1.64
0.55
2.32
1.28
1.25
1.97
1.70
2.53
2.15
2.06
-5.91
-5.03
-4.93
-8.30
-6.12
-4.73
-7.79
-0.91
1.77
1.91
1.71
0.56
-1.55
1.56
-6.62
0.85
Cyclopentanone, ID: C120923
-4.68
-4.26
-3.67
-5.02
-4.07
-3.05
-7.61
-2.18
1,1,1-trifluoropropan-2-ol C3H5F3O
-4.16
-1.92
-2.04
-2.73
-3.25
-3.13
-4.28
0.02
1-nitropropane C3H7NO2
-3.34
-6.54
-6.69
-2.30
-6.04
-2.58
-12.35
-13.24
Trimethylamine, ID: C75503
-3.42
-1.21
-2.00
-5.32
-5.19
-1.74
-5.55
-0.12
Isobutane, ID: C75285
3-methyl-1H-indole C9H9N
1,1,2-trichloro-1,2,2-trifluoro-ethane C2Cl3F3
Methane, trifluoro-, ID: C75467
0.81
0.57
0.09
-1.25
0.29
1.64
-2.00
-0.27
-2.21
-2.50
-4.14
-2.77
-1.63
-5.00
-0.59
Benzaldehyde, 4-hydroxy-, ID: C123080
-2.29
10.48
-8.59
-8.79
-11.93
-9.87
-7.90
-14.55
-4.84
1-chloro-2-(2-chloroethylsulfanyl)ethane C4H8Cl2S
-3.92
-2.94
-2.95
-2.52
-3.17
-2.31
-6.58
-0.09
Pyrrolidine, ID: C123751
-5.48
-4.61
-5.56
-4.73
-5.22
-3.71
-5.26
-1.04
Diethyl sulfide, ID: C352932
-1.43
-0.53
-0.90
-0.64
-0.96
-0.19
-1.85
1.35
2-Heptanone, ID: C110430
-3.04
-2.56
-2.47
-3.33
-2.77
-1.92
-5.31
-0.53
1.83
2.02
1.33
1.94
1.75
2.30
2.02
1.98
propioni cacid ethyl ester C4H8O2
-2.93
-4.47
-5.24
-5.80
-2.64
-1.21
-4.86
-1.96
2-Octanone, ID: C111137
-2.88
-2.50
-2.33
-3.32
-2.68
-1.64
-5.14
-0.38
Ethene, 1,2-dichloro-, (E)-, ID: C156605
-0.76
-0.25
-0.39
-0.42
-0.27
0.68
-0.88
0.33
1,1,1,3,3,3-hexafluoropropan-2-ol C3H2F6O
-3.77
-0.32
-0.46
-1.80
-1.44
-2.08
-3.09
0.60
Phenol, 3-methyl-, ID: C108394
-5.49
-4.50
-4.80
-6.08
-6.20
-5.18
-7.49
-1.51
butyric acid methyl ester C5H10O2
-2.55
-4.62
-4.42
-5.57
-2.56
-0.92
-4.76
-1.77
2-ethylpyrazine C6H8N2
-5.51
-4.53
-5.68
-7.83
-5.73
-2.92
-12.76
-2.95
Acetic acid, butyl ester, ID: C123864
-2.55
-5.53
-5.71
-5.93
-2.47
-1.05
-5.02
-1.70
Biphenyl, ID: C92524
-2.64
-2.52
-2.61
-4.35
-3.00
-1.40
-5.61
-0.42
1,2-Ethanediol, ID: C107211
-9.30
-9.70
-10.67
-11.12
-13.72
-8.27
-11.76
-4.62
3.11
2.47
2.49
1.73
-0.06
4.57
0.21
2.32
3-Pentanone, ID: C96220
-3.41
-1.51
-2.93
-2.90
-2.53
-2.48
-4.74
-0.52
Cyclohexanol, ID: C108930
-5.84
-4.37
-4.37
-4.04
-5.59
-4.48
-4.70
-1.20
Naphthalene, ID: C91203
Ethane, ID: C74840
Carbon tetrafluoride, ID: C75730
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