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 0K enthalpies (kJ mol-1)

Isomers of C8H18

2015 06 30 15:39
index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a C8H18 111659 Octane   sketch of Octane
b (CH3)3CC(CH3)3 594821 tetramethylbutane   sketch of tetramethylbutane
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
composite CBS-Q 0.0 a
-23.5 b

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) TZVP cc-pVDZ cc-pVTZ aug-cc-pVTZ
hartree fock HF 0.0 a
37.9 b
0.0 a
11.1 b
0.0 a
11.1 b
0.0 a
34.3 b
0.0 a
40.7 b
0.0 a
39.9 b
0.0 a
39.5 b
0.0 a
39.7 b
0.0 a
38.7 b
0.0 a
41.5 b
0.0 a
39.9 b
0.0 a
41.0 b
0.0 a
43.4 b
 
density functional LSDA 0.0 a
-13.6 b
0.0 a
-46.4 b
0.0 a
-46.4 b
0.0 a
-26.1 b
0.0 a
-22.3 b
0.0 a
-24.0 b
0.0 a
-22.8 b
0.0 a
-24.0 b
0.0 a
-28.0 b
0.0 a
-28.7 b
  0.0 a
-21.8 b
0.0 a
-23.5 b
 
SVWN   0.0 a
-46.4 b
    0.0 a
-22.3 b
  0.0 a
-22.5 b
      0.0 a
-26.2 b
     
BLYP 0.0 a
23.4 b
0.0 a
13.2 b
0.0 a
13.2 b
0.0 a
25.6 b
0.0 a
29.0 b
0.0 a
28.3 b
0.0 a
30.0 b
0.0 a
33.0 b
0.0 a
30.2 b
0.0 a
24.5 b
  0.0 a
31.6 b
0.0 a
33.2 b
 
B1B95 0.0 a
12.3 b
0.0 a
-19.8 b
0.0 a
-19.8 b
0.0 a
13.7 b
0.0 a
14.7 b
0.0 a
77.4 b
0.0 a
14.4 b
0.0 a
11.9 b
0.0 a
10.4 b
0.0 a
11.8 b
  0.0 a
17.4 b
0.0 a
14.1 b
 
B3LYP 0.0 a
21.5 b
0.0 a
6.2 b
0.0 a
6.2 b
0.0 a
22.4 b
0.0 a
26.5 b
0.0 a
25.5 b
0.0 a
26.6 b
0.0 a
27.9 b
0.0 a
25.3 b
0.0 a
23.0 b
0.0 a
27.7 b
0.0 a
28.4 b
0.0 a
28.8 b
0.0 a
28.0 b
B3LYPultrafine         0.0 a
26.9 b
                 
B3PW91 0.0 a
26.4 b
0.0 a
0.4 b
0.0 a
0.4 b
0.0 a
20.8 b
0.0 a
24.9 b
0.0 a
23.4 b
0.0 a
23.7 b
0.0 a
23.2 b
0.0 a
20.6 b
0.0 a
22.4 b
  0.0 a
26.1 b
0.0 a
25.7 b
 
mPW1PW91 0.0 a
22.1 b
0.0 a
-6.2 b
0.0 a
-5.9 b
0.0 a
16.2 b
0.0 a
20.2 b
0.0 a
18.6 b
0.0 a
19.0 b
0.0 a
18.4 b
0.0 a
15.7 b
0.0 a
18.2 b
  0.0 a
21.4 b
0.0 a
21.2 b
 
M06-2X     0.0 a
-7.9 b
  0.0 a
-7.9 b
                 
PBEPBE 0.0 a
16.4 b
0.0 a
-6.9 b
0.0 a
-6.9 b
0.0 a
12.3 b
0.0 a
16.1 b
0.0 a
14.7 b
0.0 a
15.8 b
0.0 a
16.4 b
0.0 a
13.2 b
0.0 a
12.6 b
  0.0 a
17.8 b
0.0 a
17.4 b
 
PBE1PBE         0.0 a
15.9 b
                 
HSEh1PBE         0.0 a
15.1 b
  0.0 a
13.9 b
             
TPSSh         0.0 a
19.6 b
  0.0 a
18.9 b
    0.0 a
17.3 b
    0.0 a
20.8 b
 
wB97X-D     0.0 a
-21.4 b
  0.0 a
-0.9 b
  0.0 a
-1.1 b
  0.0 a
-4.5 b
  0.0 a
0.4 b
0.0 a
-1.1 b
0.0 a
3.0 b
0.0 a
0.6 b
B97D3   0.0 a
-18.3 b
    0.0 a
1.4 b
      0.0 a
0.1 b
        0.0 a
2.9 b
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVTZ
Moller Plesset perturbation MP2 0.0 a
14.8 b
      0.0 a
-12.1 b
    0.0 a
-20.6 b
0.0 a
-23.2 b
  0.0 a
-29.8 b
     
MP2=FULL         0.0 a
-14.2 b
                 
MP3=FULL         0.0 a
1.2 b
  0.0 a
-5.1 b
             
B2PLYP         0.0 a
11.6 b
              0.0 a
9.5 b
 
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVTZ

Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 0.0 a
30.0 b
0.0 a
31.3 b
0.0 a
34.4 b
0.0 a
37.5 b
0.0 a
33.4 b
0.0 a
32.8 b
density functional B3LYP 0.0 a
15.1 b
0.0 a
14.8 b
0.0 a
21.5 b
0.0 a
23.1 b
0.0 a
17.4 b
0.0 a
17.4 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 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.