return to home page Computational Chemistry Comparison and Benchmark DataBase Release 18 (October 2016) Standard Reference Database 101 National Institute of Standards and Technology
You are here: Comparisons > Energy > Similar molecules > Isomers OR FAQ Help > List > Similar molecules > Isomers

Relative enthalpies of isomers - Comparison of 298.15K enthalpies (kJ mol-1)

Isomers of C4H9

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a C(CH3)3 1605738 Tert-butyl radical 0.0 sketch of Tert-butyl radical
b CH3CHCH2CH3 2348552 2-Butyl radical 15.9 sketch of 2-Butyl radical
c CH2CH(CH3)2 4630459 Isobutyl radical 21.2 sketch of Isobutyl radical
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
semi-empirical AM1 0.0 a
13.2 b
44.4 c
PM6 0.0 a
30.7 b
54.9 c
composite G1 0.0 a
16.4 b
G2MP2 0.0 a
16.1 b
G2 0.0 a
16.4 b
G3 0.0 a
15.5 b
16.9 c
G3B3 0.0 a
15.8 b
18.4 c
G4 0.0 a
16.8 b
20.1 c
CBS-Q 0.0 a
15.2 b
17.6 c
molecular mechanics DREIDING
351.9 c
MM3 0.0 a
6.5 b
-0.0 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) cc-pVDZ cc-pVTZ aug-cc-pVDZ cc-pV(T+d)Z
hartree fock HF   0.0 a
10.8 b
13.3 c
0.0 a
10.8 b
13.3 c
0.0 a
11.9 b
20.7 c
  0.0 a
11.3 b
19.4 c
0.0 a 0.0 a
10.9 b
18.4 c
 
NC
NC
  0.0 a
11.1 b
18.9 c
0.0 a
10.5 b
17.7 c
0.0 a
10.2 b
16.6 c
0.0 a
10.5 b
17.7 c
ROHF   0.0 a
341.1 b
342.9 c
    0.0 a
341.0 b
349.0 c
0.0 a
339.2 b
347.0 c
0.0 a
338.0 b
344.4 c
0.0 a
338.7 b
345.9 c
      0.0 a
336.3 b
343.8 c
0.0 a
335.3 b
342.3 c
  0.0 a
335.3 b
342.3 c
density functional LSDA 0.0 a
25.7 b
45.4 c

NC

NC
0.0 a
24.9 b
41.3 c
0.0 a
25.3 b
41.5 c

NC

NC
0.0 a
23.8 b
39.0 c

NC

NC
 
NC

NC

NC
0.0 a
23.4 b
39.1 c
BLYP   0.0 a
17.0 b
29.1 c
0.0 a
17.0 b
29.1 c
0.0 a
18.8 b
35.0 c
  0.0 a
18.5 b
34.6 c
0.0 a
17.0 b
31.7 c
0.0 a
17.4 b
33.3 c
      0.0 a
17.4 b
33.1 c
0.0 a
17.0 b
32.8 c
  0.0 a
17.0 b
32.8 c
B1B95
NC

NC

NC

NC

NC

NC

NC

NC

NC

NC
 
NC

NC

NC
0.0 a
17.2 b
30.9 c
B3LYP   0.0 a
16.1 b
26.0 c
0.0 a
16.1 b
26.0 c
0.0 a
17.7 b
32.4 c
0.0 a
17.8 b
32.3 c
0.0 a
17.4 b
31.9 c
0.0 a
16.1 b
29.1 c
0.0 a
16.5 b
30.5 c
  0.0 a
17.7 b
31.5 c
 
NC
0.0 a
16.1 b
30.1 c
0.0 a
15.5 b
27.9 c
0.0 a
16.1 b
30.1 c
B3PW91
NC
NC
0.0 a
16.2 b
25.3 c
0.0 a
16.2 b
25.3 c
0.0 a
17.7 b
32.6 c
0.0 a
17.8 b
32.4 c
0.0 a
17.6 b
32.2 c
0.0 a
16.3 b
29.6 c
0.0 a
NC
NC

  b
  c
  0.0 a
17.0 b
31.4 c
0.0 a
NC
NC
0.0 a
mPW1PW91   0.0 a
16.2 b
23.9 c
    0.0 a
31.3 c
0.0 a
17.5 b
31.1 c
0.0 a
16.3 b
28.4 c
0.0 a
16.7 b
29.6 c
      0.0 a
17.0 b
30.5 c
0.0 a
16.5 b
29.8 c
  0.0 a
16.5 b
29.8 c
PBEPBE                             0.0 a
18.7 b
34.0 c
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) cc-pVDZ cc-pVTZ aug-cc-pVDZ cc-pV(T+d)Z
Moller Plesset perturbation MP2
NC
NC
0.0 a
15.6 b
15.0 c
0.0 a
15.6 b
15.0 c
0.0 a
17.5 b
21.6 c
  0.0 a
16.6 b
20.2 c
0.0 a  
NC
NC
0.0 a
16.8 b
19.2 c
    0.0 a 0.0 a
15.6 b
15.5 c
0.0 a
MP2=FULL   0.0 a
15.7 b
15.0 c
    0.0 a
17.5 b
21.4 c
0.0 a
16.8 b
20.3 c
0.0 a
16.7 b
17.9 c
0.0 a
17.2 b
19.2 c

NC
NC
    0.0 a
16.0 b
18.6 c
     
MP4        
NC
                   
Configuration interaction CID         0.0 a
14.8 b
21.2 c
                   
CISD         0.0 a
15.0 b
21.6 c
                   
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) cc-pVDZ cc-pVTZ aug-cc-pVDZ cc-pV(T+d)Z
Quadratic configuration interaction QCISD   0.0 a
15.0 b
16.1 c
    0.0 a
16.3 b
23.1 c
    0.0 a
15.8 b
20.9 c
             
Coupled Cluster CCD         0.0 a
21.8 c
                   
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) cc-pVDZ cc-pVTZ aug-cc-pVDZ 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
9.5 b
14.6 c
0.0 a
9.6 b
13.3 c
0.0 a
11.3 b
18.6 c
0.0 a
10.9 b
17.0 c
0.0 a
10.7 b
17.7 c
0.0 a
10.8 b
17.8 c
density functional B1B95
-72792.3 c
0.0 a
14.4 b
25.0 c
       
B3LYP 0.0 a
12.9 b
23.3 c
0.0 a
13.6 b
22.7 c
0.0 a
15.5 b
27.8 c
0.0 a
15.6 b
26.9 c
0.0 a
15.5 b
27.6 c
0.0 a
15.4 b
27.6 c
Moller Plesset perturbation MP2 0.0 a
14.5 b
13.2 c
0.0 a
15.0 b
13.6 c
0.0 a
16.6 b
16.1 c
0.0 a
17.5 b
16.6 c
0.0 a
14.8 b
13.8 c
0.0 a
14.9 b
13.9 c

Single point energy calculations (select basis sets)
6-311+G(3df,2p) cc-pVDZ cc-pVTZ aug-cc-pVDZ cc-pV(T+d)Z
Moller Plesset perturbation MP2FC// HF/6-31G* 0.0 a
16.1 b
16.8 c
0.0 a
15.2 b
17.5 c
0.0 a
14.7 b
20.8 c
0.0 a
13.4 b
21.9 c
0.0 a
14.7 b
20.8 c
MP2FC// B3LYP/6-31G* 0.0 a
16.1 b
17.4 c
0.0 a
15.2 b
18.2 c
0.0 a
14.9 b
17.2 c
0.0 a
14.7 b
14.5 c
0.0 a
14.9 b
17.2 c
MP2FC// MP2FC/6-31G* 0.0 a
17.2 c
0.0 a
17.7 c
0.0 a
16.9 c
0.0 a
15.2 b
14.6 c
0.0 a
16.9 c
MP4// HF/6-31G*
NC
NC
0.0 a
14.3 b
19.0 c

NC
NC
  0.0 a
14.6 b
17.7 c
MP4// B3LYP/6-31G*  
NC
NC

NC
NC
  0.0 a
14.7 b
18.5 c
MP4// MP2/6-31G* 0.0 a
18.7 c
 
NC
  0.0 a
18.0 c
Coupled Cluster CCSD// HF/6-31G*   0.0 a
14.3 b
19.0 c
     
CCSD(T)// HF/6-31G*   0.0 a
15.0 b
19.2 c
     
CCSD// B3LYP/6-31G* 0.0 a
19.0 c
0.0 a
14.3 b
19.7 c
     
CCSD(T)// B3LYP/6-31G*
NC
0.0 a
15.1 b
19.9 c
     
CCSD(T)//B3LYP/6-31G(2df,p)     0.0 a   0.0 a
CCSD// MP2FC/6-31G* 0.0 a
18.6 c
    0.0 a
13.9 b
16.0 c
 
CCSD(T)// MP2FC/6-31G*
NC
    0.0 a
14.6 b
16.0 c
 
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 Calculated; Vibrations; Scale Factors; Scale factors to list vibrational scaling factors.
See section Calculated; Vibrations; Scale Factors; Calculate a scale factor to calculate a vibrational scaling factor for a given set of molecules.