A set of 148 molecules having well-established enthalpies of formation at 298 K is presented. This set, referred to as the G2 neutral test set, includes the 55 molecules whose atomization energies were used to test Gaussian-2 (G2) theory [J. Chem. Phys. 94, 7221 (1991)] and 93 new molecules. The G2 test set includes 29 radicals, 35 nonhydrogen systems, 22 hydrocarbons, 47 substituted hydrocarbons, and 15 inorganic hydrides. It is hoped that this new test set will provide a means for assessing and improving new theoretical models. From an assessment of G2 and density functional theories (DFT) on this test set it is found that G2 theory is the most reliable method both in terms of average absolute deviation (1.58 kcal/mol) and maximum deviation (8.2 kcal/mol). The largest deviations between experiment and G2 theory occur for molecules having multiple halogens. Inclusion of spin–orbit effects reduces the average absolute deviation to 1.47 kcal/mol and significantly improves the results for the chlorine substituted molecules, but little overall improvement is seen for the fluorine substituted molecules. Of the two modified versions of G2 theory examined in this study, G2(MP2,SVP) theory (average absolute deviation=1.93 kcal/mol) performs better than G2(MP2) theory (2.04 kcal/mol). The G2(MP2,SVP) theory is found to perform very well for hydrocarbons, radicals, and inorganic hydrides. Of the seven DFT methods investigated, the B3LYP method has the smallest average absolute deviation (3.11 kcal/mol). It also has a significantly larger distribution of error than the G2 methods with a maximum deviation of 20.1 kcal/mol.

Topics
Density functional theory, Spin-orbit interactions, Thermodynamic functions, Descriptive statistics
1.
L. A.
Curtiss
,
K.
Raghavachari
,
G. W.
Trucks
, and
J. A.
Pople
,
J. Chem. Phys.
94
,
7221
(
1991
).
Google Scholar
Crossref
Search ADS
 
2.
For reviews see, L. A. Curtiss and K. Raghavachari, in Quantum Mechanical Electronic Structure Calculations with Chemical Accuracy, edited by S. R. Langhoff (Kluwer Academic, Netherlands, 1995), p. 139;
K. Raghavachari and L. A. Curtiss, in Modern Electronic Structure Theory, edited by D. R. Yarkony (World Scientific, Singapore, 1995), p. 991.
3.
L. A.
Curtiss
,
J. E.
Carpenter
,
K.
Raghavachari
, and
J. A.
Pople
,
J. Chem. Phys.
96
,
9030
(
1992
).
Google Scholar
Crossref
Search ADS
 
4.
L. A.
Curtiss
,
K.
Raghavachari
, and
J. A.
Pople
,
J. Chem. Phys.
103
,
4192
(
1995
).
Google Scholar
Crossref
Search ADS
 
5.
L. A.
Curtiss
,
K.
Raghavachari
, and
J. A.
Pople
,
J. Chem. Phys.
98
,
1293
(
1993
).
Google Scholar
Crossref
Search ADS
 
6.
(a)
B. J.
 
Smith
 and
L.
 
Radom
,
J. Phys. Chem.
 
99
,
6468
(
1995
);
Google Scholar
Crossref
Search ADS
 
(b)
L. A.
Curtiss
,
P.
Redfern
,
B. J.
Smith
, and
L.
Radom
,
J. Chem. Phys.
104
,
5148
(
1996
).
Google Scholar
Crossref
Search ADS
 
7.
C. W.
Bauschlicher
 and
H.
Partridge
,
J. Chem. Phys.
103
,
1788
(
1995
).
Google Scholar
Crossref
Search ADS
 
8.
A. M.
 
Mebel
,
K.
 
Morokuma
, and
M. C.
 
Lin
,
J. Chem. Phys.
 
101
,
3916
(
1994
);
Google Scholar
Crossref
Search ADS
 
A. M.
Mebel
,
K.
Morokuma
, and
M. C.
Lin
,
J. Chem. Phys.
103
,
7414
(
1995
).
Google Scholar
Crossref
Search ADS
 
9.
G. A.
Petersson
,
T. G.
Tensfeldt
, and
J. A.
Montgomery
, Jr.,
J. Chem. Phys.
94
,
6091
(
1991
).
Google Scholar
Crossref
Search ADS
 
10.
J. A.
Montgomery
, Jr.,
J. W.
Ochterski
, and
G. A.
Petersson
,
J. Chem. Phys.
101
,
5900
(
1994
).
Google Scholar
Crossref
Search ADS
 
11.
J. W.
 
Ochterski
,
G. A.
 
Petersson
, and
K.
 
Wiberg
,
J. Am. Chem. Soc.
 
117
,
11299
(
1995
);
Google Scholar
Crossref
Search ADS
 
J. W.
Ochterski
,
G. A.
Petersson
, and
J. A.
Montgomery
,
J. Chem. Phys.
104
,
2598
(
1996
).
Google Scholar
Crossref
Search ADS
 
12.
P. E. M.
Siegbahn
,
M. R. A.
Blomberg
, and
M.
Svensson
,
Chem. Phys. Lett.
223
,
35
(
1994
).
Google Scholar
Crossref
Search ADS
 
13.
C. W.
Bauschlicher
 and
H.
Partridge
,
Chem. Phys. Lett.
240
,
533
(
1995
).
Google Scholar
Crossref
Search ADS
 
14.
C. W.
Bauschlicher
,
Chem. Phys. Lett.
246
,
40
(
1995
).
Google Scholar
Crossref
Search ADS
 
15.
A. D.
Becke
,
J. Chem. Phys.
98
,
5648
(
1993
).
Google Scholar
Crossref
Search ADS
 
16.
M. J. Frisch, G. W. Trucks, H. B. Schlegel, P. M. W. Gill, B. G. Johnson, M. A. Robb, J. R. Cheeseman, T. A. Keith, G. A. Petersson, J. A. Montgomery, K. Raghavachari, M. A. Al-Laham, V. G. Zakrzewski, J. V. Ortiz, J. B. Foresman, J. Cioslowski, B. B. Stefanov, A. Nanayakkara, M. Challacombe, C. Y. Peng, P. Y. Ayala, W. Chen, M. W. Wong, J. L. Andres, E. S. Replogle, R. Gomperts, R. L. Martin, D. J. Fox, J. S. Binkley, D. J. Defrees, J. Baker, J. P. Stewart, M. Head-Gordon, C. Gonzales, and J. A. Pople, GAUSSIAN 94, Gaussian, Inc. Pittsburgh, 1995.
17.
J. C. Slater, The Self-Consistent Field for Molecules and Solids: Quantum Theory of Molecules and Solids (McGraw-Hill, New York, 1974), Vol. 4.
18.
S. H.
Vosko
,
L.
Wilk
, and
M.
Nusair
,
Can. J. Phys.
58
,
1200
(
1980
).
Google Scholar
Crossref
Search ADS
 
19.
A. D.
Becke
,
Phys. Rev. A
38
,
3098
(
1988
).
Google Scholar
Crossref
Search ADS
 
20.
J. P.
Perdew
 and
Y.
Wang
,
Phys. Rev. B
45
,
13244
(
1992
).
Google Scholar
Crossref
Search ADS
 
21.
J. P.
 
Perdew
,
Phys. Rev. B
 
33
,
8822
(
1986
);
Google Scholar
Crossref
Search ADS
 
J. P.
Perdew
,
B
34
,
7406
(E) (
1986
).
Google Scholar
 
22.
P. M. W.
Gill
,
B. G.
Johnson
,
J. A.
Pople
, and
M. J.
Frisch
,
Int. J. Quantum Chem. S
26
,
319
(
1992
).
Google Scholar
 
23.
C.
Lee
,
W.
Yang
, and
R. G.
Parr
,
Phys. Rev. B
37
,
785
(
1988
).
Google Scholar
Crossref
Search ADS
 
24.
L. A.
Curtiss
,
K.
Raghavachari
,
P. W.
Deutsch
, and
J. A.
Pople
,
J. Chem. Phys.
95
,
2433
(
1991
).
Google Scholar
Crossref
Search ADS
 
25.
M. W.
Chase
, Jr.,
C. A.
Davies
,
J. R.
Downey
, Jr.,
D. J.
Frurip
,
R. A.
McDonald
, and
A. N.
Syverud
,
J. Phys. Chem. Ref. Data
14
, Suppl. No.
1
(
1985
).
Google Scholar
 
26.
B.
Ruscic
,
C. A.
Mayhew
, and
J.
Berkowitz
,
J. Chem. Phys.
88
,
5580
(
1988
).
Google Scholar
Crossref
Search ADS
 
27.
E.
Storms
 and
B.
Mueller
,
J. Phys. Chem.
81
,
318
(
1977
).
Google Scholar
Crossref
Search ADS
 
28.
R. S.
Grev
 and
H. F.
Schaefer
III,
J. Chem. Phys.
97
,
8389
(
1992
).
Google Scholar
Crossref
Search ADS
 
29.
G. N. Lewis and M. Randall, Thermodynamics, 2nd ed., revised by K. S. Pitzer and L. Brewer (McGraw-Hill, New York, 1961).
30.
The MP2(FULL)/6‐31G(d) geometries, zero-point energies, and thermal corrections for the G2-1 and G2-2 neutral test sets may be obtained via anonymous FTP from axp.cmt.anl.gov. The files are located in the directory g2testsets.
31.
J. B. Pedley, R. D. Naylor, and S. P. Kirby, Thermochemical Data of Organic Compounds, 2nd ed. (Chapman and Hall, New York, 1986).
32.
J.
Berkowitz
,
G. B.
Ellison
, and
D.
Gutman
,
J. Phys. Chem.
78
,
2744
(
1994
).
Google Scholar
 
33.
The experimental sources for the atomization energies are listed in the papers on G1 theory:
J. A.
 
Pople
,
M.
 
Head-Gordon
,
D. J.
 
Fox
,
K.
 
Raghavachari
, and
L. A.
 
Curtiss
,
J. Chem. Phys.
 
90
,
5622
(
1989
);
Google Scholar
Crossref
Search ADS
 
L. A.
Curtiss
,
C.
Jones
,
G. W.
Trucks
,
K.
Raghavachari
, and
J. A.
Pople
,
J. Chem. Phys.
93
,
2537
(
1990
).,
J. Chem. Phys.
Google Scholar
Crossref
Search ADS
 
34.
K. Huber and G. Herzberg, Molecular Spectra and Molecular Structure 4. Constants of Diatomic Molecules (Van Nostrand, Princeton, 1979).
35.
In Ref. 1 this average absolute deviation was listed as 1.16 kcal/mol⁠.
36.
J. A.
Pople
 and
L. A.
Curtiss
,
J. Phys. Chem.
91
,
155
(
1987
).
Google Scholar
Crossref
Search ADS
 
37.
L. A.
Curtiss
,
M. P.
McGrath
,
J.-P.
Blaudeau
,
N. E.
Davis
,
R. C.
Binning
, and
L.
Radom
,
J. Chem. Phys.
103
,
6104
(
1995
).
Google Scholar
Crossref
Search ADS
 
38.
Spin—orbit corrections for the atoms are taken to be the energy difference between the spin—orbit-coupled ground state and the weighted J-averaged state. For example, for Cl atom the correction is ΔE(SO) = −2/6[ΔE(2P1/2−2P3/2)] and for S atom the correction is ΔE(SO) = −{3/9[ΔE(3P1−3P2)]+1/9[ΔE(3P0−3P2)]}⁠. For the Π2 molecules it is taken to be the energy difference between a weighted Ω-averaged state and the spin-coupled ground state, i. e., ΔE(SO) = −|ΔE(2Π3/2−2Π1/2)|⁠.
39.
C. Moore, Natl. Bur. Stand. (U.S.) Circ. 467 (1952).
40.
H. H.
Michels
 and
R. H.
Hobbs
,
Chem. Phys. Lett.
207
,
389
(
1993
).
Google Scholar
Crossref
Search ADS
 
41.
L. V. Gurvich, I. V. Veyts, and C. B. Alcock, Thermodynamic Properties of Individual Substances, 4th ed. (Hemisphere, New York, 1989), Vols. I–III.
42.
L. A. Curtiss, K. Raghavachari, P. C. Redfern, and J. A. Pople, Chem. Phys. Lett. (to be submitted).
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