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Computational Chemistry Comparison and Benchmark DataBase
Release 18October 2016
NIST Standard Reference Database 101
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XXH-bond dimers
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IV.A.4. (XIV.F.)

Relative enthalpies of isomers - Comparison of 0K enthalpies (kJ mol-1)

Isomers of C3H4N2

2015 06 30 15:39
index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a C3H4N2 288131 1H-Pyrazole   sketch of 1H-Pyrazole
b C3H4N2 288324 1H-Imidazole   sketch of 1H-Imidazole
c C3H4N2 9000162 4H-Imidazole   sketch of 4H-Imidazole
d C3H4N2 9000173 2H-Imidazole   sketch of 2H-Imidazole
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
composite G3 0.0 a
-46.8 b
G3B3 0.0 a
-46.9 b
14.0 c
G3MP2 0.0 a
-46.3 b
CBS-Q 0.0 a
-46.7 b
19.3 c

Methods with standard basis sets
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z
hartree fock HF 0.0 a
-28.1 b
3.5 c
0.0 a
-61.3 b
29.2 c
0.0 a
-61.3 b
29.2 c
0.0 a
-50.8 b
42.7 c
0.0 a
-55.2 b
-14.0 c
0.0 a
-55.4 b
-6.6 c
0.0 a
-56.0 b
-2.5 c
0.0 a
-54.7 b
-11.6 c
0.0 a
-55.4 b
-4.7 c
0.0 a
-55.7 b
-9.6 c
0.0 a
-57.8 b
0.0 a
-55.4 b
-1.9 c
185.8 d
0.0 a
-54.3 b
-5.8 c
0.0 a
-55.8 b
-4.0 c
0.0 a
-55.3 b
-8.6 c
0.0 a
-56.3 b
-4.0 c
0.0 a
-55.8 b
density functional LSDA 0.0 a
-18.1 b
58.8 c
0.0 a
-47.1 b
62.2 c
0.0 a
-47.1 b
62.2 c
0.0 a
-38.5 b
72.7 c
0.0 a
-39.4 b
41.0 c
0.0 a
-39.7 b
47.0 c
0.0 a
-40.1 b
48.6 c
0.0 a
-41.2 b
44.9 c
0.0 a
-41.7 b
52.0 c
0.0 a
-39.9 b
50.8 c
 
NC
NC
0.0 a
-39.5 b
51.5 c
0.0 a
-41.0 b
53.8 c
0.0 a
-40.4 b
50.0 c

NC
NC
0.0 a
-41.0 b
SVWN  
NC
NC
NC
   
NC
NC
NC

NC
NC

NC
NC
NC

NC
NC

NC
NC

NC
NC
  0.0 a
-41.3 b
51.6 c
223.1 d

NC
NC

NC
NC

NC
NC

NC
NC
 
BLYP 0.0 a
-14.5 b
22.8 c
0.0 a
-42.1 b
35.0 c
0.0 a
-42.1 b
35.0 c
0.0 a
-35.5 b
45.5 c
0.0 a
-38.7 b
14.0 c
11.1 d
0.0 a
-38.9 b
20.3 c
0.0 a
-39.8 b
23.0 c
0.0 a
-40.0 b
19.9 c
0.0 a
-40.5 b
26.6 c
0.0 a
-39.8 b
23.7 c
 
NC
NC
0.0 a
-38.5 b
26.9 c
0.0 a
-40.8 b
27.6 c
0.0 a
-39.5 b
25.8 c

NC
NC
0.0 a
-40.8 b
B1B95 0.0 a
-15.5 b
37.9 c
0.0 a
-38.0 b
56.1 c
0.0 a
-38.0 b
56.1 c
0.0 a
-27.5 b
71.2 c
0.0 a
-43.0 b
20.5 c
0.0 a
-12.0 b
36.8 c
0.0 a
-33.6 b
39.6 c
0.0 a
-33.6 b
34.0 c
0.0 a
-34.2 b
40.9 c
0.0 a
-34.6 b
38.2 c
 
NC
NC
0.0 a
-33.4 b
39.7 c
0.0 a
-44.3 b
32.2 c
0.0 a
-43.5 b
28.9 c

NC
NC
0.0 a
-44.3 b
B3LYP 0.0 a
-18.4 b
26.2 c
0.0 a
-46.9 b
39.5 c
0.0 a
-46.9 b
39.4 c
0.0 a
-39.1 b
50.8 c
0.0 a
-42.3 b
14.4 c
0.0 a
-42.5 b
21.0 c
0.0 a
-43.3 b
23.9 c
0.0 a
-43.3 b
19.5 c
0.0 a
-43.8 b
26.4 c
0.0 a
-43.2 b
23.6 c
0.0 a
-45.5 b
0.0 a
-43.9 b
27.2 c
217.1 d
0.0 a
-41.8 b
26.4 c
0.0 a
-44.1 b
27.6 c
0.0 a
-42.9 b
25.3 c
0.0 a
-44.4 b
27.5 c
0.0 a
-44.1 b
B3LYPultrafine  
NC
NC
    0.0 a
-42.2 b
14.5 c

NC
NC

NC
NC

NC
NC
     
NC
NC

NC
NC
0.0 a
-44.1 b
27.6 c

NC
NC
0.0 a
-44.4 b
27.5 c
 
B3PW91 0.0 a
-17.9 b
31.0 c
0.0 a
-46.8 b
45.2 c
0.0 a
-46.8 b
45.2 c
0.0 a
-38.6 b
57.1 c
0.0 a
-41.2 b
21.0 c
0.0 a
-41.5 b
27.6 c
0.0 a
-42.0 b
29.6 c
0.0 a
-42.4 b
24.3 c
0.0 a
-42.9 b
31.3 c
0.0 a
-41.9 b
29.4 c
 
NC
NC
0.0 a
-40.9 b
30.9 c
0.0 a
-42.6 b
32.8 c
0.0 a
-41.6 b
29.4 c

NC
NC
0.0 a
-42.6 b
mPW1PW91 0.0 a
-18.6 b
31.4 c
0.0 a
-52.4 b
41.5 c
0.0 a
-48.0 b
46.2 c
0.0 a
-39.2 b
58.4 c
0.0 a
-46.1 b
16.7 c
0.0 a
-46.3 b
23.5 c
0.0 a
-46.8 b
25.8 c
0.0 a
-47.1 b
19.8 c
0.0 a
-43.6 b
31.0 c
0.0 a
-42.5 b
29.0 c
 
NC
NC
0.0 a
-45.8 b
26.2 c
0.0 a
-43.1 b
32.6 c
0.0 a
-42.3 b
28.8 c

NC
NC
0.0 a
-43.1 b
M06-2X
NC
NC

NC
NC

NC
NC
NC

NC
NC
0.0 a
-47.3 b
17.8 c
213.4 d

NC
NC

NC
NC

NC
NC

NC
NC

NC
NC
 
NC
NC

NC
NC

NC
NC

NC
NC

NC
NC
 
PBEPBE 0.0 a
-14.4 b
32.1 c
0.0 a
-42.7 b
42.7 c
0.0 a
-42.7 b
42.7 c
0.0 a
-35.1 b
54.3 c
0.0 a
-37.3 b
23.3 c
0.0 a
-37.6 b
29.8 c
0.0 a
-38.2 b
31.9 c
0.0 a
-38.8 b
27.3 c
0.0 a
-39.3 b
34.3 c
0.0 a
-38.1 b
32.2 c
0.0 a
-40.6 b

NC
NC
0.0 a
-37.3 b
34.3 c
0.0 a
-39.0 b
35.9 c
0.0 a
-37.8 b
33.0 c

NC
NC
0.0 a
-39.0 b
PBEPBEultrafine  
NC
NC
    0.0 a
-37.3 b
23.3 c

NC
NC

NC
NC

NC
NC
     
NC
NC

NC
NC

NC
NC

NC
NC

NC
NC
 
PBE1PBE
NC
NC

NC
NC

NC
NC

NC
NC
0.0 a
-41.3 b
22.2 c
217.2 d

NC
NC

NC
NC

NC
NC

NC
NC

NC
NC
 
NC
NC

NC
NC

NC
NC

NC
NC

NC
NC
 
HSEh1PBE
NC
NC
0.0 a
-47.9 b
46.7 c
262.2 d

NC
NC

NC
NC

NC
NC

NC
NC
0.0 a
-42.1 b
31.0 c
220.4 d

NC
NC

NC
NC

NC
NC
 
NC
NC

NC
NC
0.0 a
-42.6 b
34.0 c
217.8 d

NC
NC

NC
NC
 
TPSSh  
NC
NC

NC
NC

NC
NC
0.0 a
-39.8 b
16.6 c

NC
NC
0.0 a
-40.8 b
25.1 c

NC
NC
  0.0 a
-40.5 b
24.4 c
23.7 d
 
NC
NC

NC
NC
0.0 a
-41.3 b
28.0 c

NC
NC

NC
NC
 
wB97X-D
NC
NC

NC
NC
0.0 a
-48.7 b
47.1 c
45.2 d

NC
NC
0.0 a
-43.4 b
17.7 c
18.3 d

NC
NC
0.0 a
-44.2 b
26.1 c
28.0 d

NC
NC
0.0 a
-44.9 b
27.8 c
29.1 d

NC
NC
  0.0 a
-44.0 b
32.6 c
33.4 d
0.0 a
-48.3 b
26.1 c
28.0 d
0.0 a
-44.8 b
28.6 c
31.2 d

NC
NC
0.0 a
-45.2 b
28.0 c
30.9 d
 
B97D3   0.0 a
-42.5 b
38.3 c
33.8 d
    0.0 a
-38.2 b
17.4 c
14.5 d
      0.0 a
-39.7 b
28.4 c
26.3 d
            0.0 a
-40.2 b
29.5 c
29.0 d
 
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z
Moller Plesset perturbation MP2 0.0 a
-19.0 b
-8.3 c
0.0 a
-43.1 b
30.4 c
0.0 a
-43.1 b
30.4 c
0.0 a
-35.8 b
42.0 c
0.0 a
-41.4 b
22.3 c
18.7 d
0.0 a
-41.7 b
27.5 c

NC
NC
0.0 a
-41.3 b
26.1 c
22.3 d
0.0 a
-42.2 b
30.6 c
0.0 a
-42.1 b
33.6 c
  0.0 a
-42.8 b
30.5 c
229.1 d
0.0 a
-40.8 b
30.1 c
0.0 a
-42.4 b
37.2 c

NC
NC
  0.0 a
-42.4 b
MP2=FULL
NC
NC

NC
NC

NC
NC

NC
NC
0.0 a
-41.8 b
23.0 c
0.0 a
-42.1 b
28.2 c
0.0 a
-42.8 b
31.0 c
0.0 a
-41.4 b
27.3 c
0.0 a
-42.4 b
31.7 c

NC
NC
 
NC
NC

NC
NC

NC
NC

NC
NC

NC
NC
 
MP3         0.0 a
-45.5 b
6.5 c
 
NC
NC
       
NC
NC

NC
NC
       
MP3=FULL  
NC
NC

NC
NC

NC
NC
0.0 a
-45.9 b
7.1 c

NC
NC
0.0 a
-47.0 b
15.2 c

NC
NC

NC
NC

NC
NC
 
NC
NC

NC
NC

NC
NC

NC
NC
   
MP4  
NC
NC
   
NC
NC
     
NC
NC
   
NC
NC
 
NC
NC
     
MP4=FULL  
NC
NC
                   
NC
NC

NC
NC
     
B2PLYP
NC
NC

NC
NC

NC
NC

NC
NC

NC
NC
NC

NC
NC

NC
NC

NC
NC

NC
NC

NC
NC
 
NC
NC

NC
NC
0.0 a
-44.1 b
27.1 c

NC
NC

NC
NC
 
B2PLYP=FULL
NC
NC

NC
NC

NC
NC

NC
NC

NC
NC

NC
NC

NC
NC

NC
NC

NC
NC

NC
NC
 
NC
NC

NC
NC

NC
NC

NC
NC
   
B2PLYP=FULLultrafine
NC
NC

NC
NC

NC
NC

NC
NC
0.0 a
-47.8 b
5.1 c

NC
NC

NC
NC

NC
NC

NC
NC

NC
NC
 
NC
NC

NC
NC

NC
NC

NC
NC

NC
NC
 
Configuration interaction CID  
NC
NC

NC
NC

NC
NC
0.0 a
-49.2 b
3.1 c
   
NC
NC
                 
CISD  
NC
NC

NC
NC

NC
NC
0.0 a
-49.2 b
1.9 c
   
NC
NC
                 
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z
Quadratic configuration interaction QCISD   0.0 a
-47.5 b
16.2 c

NC
NC

NC
NC
0.0 a
-46.0 b
-1.8 c
0.0 a
-46.4 b
3.4 c
0.0 a
-47.3 b
6.2 c

NC
NC
0.0 a
-46.4 b
5.5 c

NC
NC
   
NC
NC

NC
NC

NC
NC
   
QCISD(T)        
NC
NC
   
NC
NC
     
NC
NC
 
NC
NC
     
QCISD(T)=FULL        
NC
NC
 
NC
NC
                   
Coupled Cluster CCD  
NC
NC

NC
NC

NC
NC
0.0 a
-45.9 b
2.9 c

NC
NC

NC
NC

NC
NC

NC
NC

NC
NC
 
NC
NC

NC
NC

NC
NC

NC
NC
   
CCSD        
NC
NC
       
NC
NC
 
NC
NC

NC
NC

NC
NC

NC
NC
   
CCSD=FULL        
NC
NC
       
NC
NC
   
NC
NC

NC
NC

NC
NC
   
CCSD(T)        
NC
NC

NC
NC
 
NC
NC
     
NC
NC

NC
NC
 
NC
NC
   
CCSD(T)=FULL        
NC
NC
           
NC
NC

NC
NC
       
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z

Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 0.0 a
-48.3 b
34.2 c
0.0 a
-58.5 b
-26.7 c
0.0 a
-47.0 b
37.7 c
0.0 a
-55.5 b
-18.9 c
0.0 a
-46.0 b
45.5 c
0.0 a
-46.0 b
45.4 c
density functional B1B95 0.0 a
-42.0 b
0.0 a
-49.7 b
       
B3LYP 0.0 a
-39.7 b
42.5 c
0.0 a
-47.8 b
0.6 c
0.0 a
-37.2 b
47.7 c
0.0 a
-44.0 b
8.4 c
0.0 a
-37.9 b
54.2 c
0.0 a
-38.0 b
53.9 c
wB97X-D
NC
NC

NC
NC

NC
NC

NC
NC

NC
NC

NC
NC
Moller Plesset perturbation MP2 0.0 a
-33.8 b
38.0 c
0.0 a
-45.2 b
8.0 c
0.0 a
-33.1 b
42.8 c
0.0 a
-42.0 b
17.7 c
0.0 a
-33.4 b
49.0 c
0.0 a
-33.3 b
48.6 c

Single point energy calculations (select basis sets)
6-311+G(3df,2p) cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z
Moller Plesset perturbation MP2FC// HF/6-31G*   0.0 a
-41.4 b
0.0 a
-43.5 b
    0.0 a
-43.5 b
MP2FC// B3LYP/6-31G*   0.0 a
-41.0 b
       
MP2FC// MP2FC/6-31G* 0.0 a
-44.8 b
    0.0 a
-42.2 b
0.0 a
-42.8 b
 
MP4// HF/6-31G*   0.0 a
-45.0 b
       
MP4// MP2/6-31G* 0.0 a
-50.4 b
         
Coupled Cluster CCSD// HF/6-31G*   0.0 a
-45.0 b
0.0 a
-47.8 b
    0.0 a
-47.8 b
CCSD(T)// HF/6-31G*   0.0 a
-43.4 b
0.0 a
-45.9 b
    0.0 a
-45.9 b
CCSD(T)//B3LYP/6-31G(2df,p)     0.0 a
-45.3 b
    0.0 a
-45.3 b
CCSD// MP2FC/6-31G* 0.0 a
-50.4 b
      0.0 a
-48.5 b
 
CCSD(T)// MP2FC/6-31G* 0.0 a
-47.8 b
      0.0 a
-45.9 b
 
NC = not calculated
For descriptions of the methods (AM1, HF, MP2, ...) and basis sets (3-21G, 3-21G*, 6-31G, ...) see the glossary in section I.C. Predefined means the basis set used is determined by the method.
gaw refers to the group additivity method implemeted in the NIST Chemistry Webbook.

See section III.C.1 List or set vibrational scaling factors to change the scale factors used here.
See section III.C.2 Calculate a vibrational scaling factor for a given set of molecules to determine the least squares best scaling factor.