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IV.A.4. (XIV.F.)

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

Isomers of C8H8

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a C6H5CHCH2 100425 Styrene   sketch of Styrene
b C8H8 277101 cubane   sketch of cubane
c C8H8 629209 cyclooctatetraene   sketch of cyclooctatetraene
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
composite G1 0.0 a
482.6 b
152.5 c
G2MP2 0.0 a
462.7 b
150.6 c
G2 0.0 a
462.7 b
150.9 c
G3 0.0 a
475.7 b
152.7 c
G3B3
NC
NC
G3MP2 0.0 a
480.8 b
151.1 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
158.5 b
197.2 c
0.0 a
466.4 b
170.2 c
0.0 a
466.4 b
170.2 c
0.0 a
594.1 b
174.4 c
  0.0 a
508.5 b
161.7 c
0.0 a
527.1 b
159.5 c
0.0 a
519.3 b
156.4 c
0.0 a
521.6 b
157.5 c
0.0 a
507.7 b
155.5 c
0.0 a
532.1 b
156.2 c
0.0 a
534.3 b
159.3 c
0.0 a
517.3 b
158.9 c
0.0 a
536.7 b
157.7 c
0.0 a
514.7 b
156.3 c
0.0 a
538.2 b
157.1 c
0.0 a
536.7 b
157.7 c
density functional LSDA 0.0 a
142.5 b
205.5 c
0.0 a
326.3 b
162.8 c
0.0 a
326.3 b
162.8 c
0.0 a
440.9 b
172.2 c
0.0 a
372.9 b
169.2 c
0.0 a
373.2 b
168.8 c
0.0 a
384.4 b
163.3 c
0.0 a
386.6 b
158.3 c
0.0 a
387.9 b
159.2 c
0.0 a
367.3 b
167.0 c
    0.0 a
363.8 b
163.9 c
0.0 a
402.7 b
162.1 c
0.0 a
376.0 b
160.0 c
  0.0 a
402.7 b
162.1 c
SVWN   0.0 a
326.2 b
162.7 c
    0.0 a
373.0 b
169.2 c
  0.0 a
384.4 b
163.3 c
                   
BLYP 0.0 a
265.6 b
190.1 c
0.0 a
444.2 b
162.4 c
0.0 a
444.2 b
162.4 c
0.0 a
574.2 b
167.3 c
0.0 a
516.0 b
163.9 c
0.0 a
515.7 b
163.5 c
0.0 a
530.6 b
159.3 c
0.0 a
533.8 b
155.8 c
0.0 a
534.9 b
0.0 a
516.2 b
    0.0 a
511.1 b
160.5 c
0.0 a
552.6 b
157.7 c
0.0 a
522.8 b
156.3 c
  0.0 a
552.6 b
157.7 c
B1B95 0.0 a
164.7 b
203.3 c
0.0 a
339.5 b
165.1 c
0.0 a
339.5 b
165.1 c
0.0 a
465.9 b
173.7 c
0.0 a
401.9 b
170.0 c
0.0 a
404.7 b
169.6 c
0.0 a
416.7 b
165.9 c
0.0 a
414.9 b
162.9 c
0.0 a
415.8 b
163.7 c
0.0 a
399.6 b
169.4 c
    0.0 a
399.2 b
166.2 c
0.0 a
424.2 b
167.8 c
0.0 a
399.5 b
164.7 c
  0.0 a
424.2 b
167.8 c
B3LYP 0.0 a
227.7 b
196.7 c
0.0 a
429.8 b
166.6 c
0.0 a
429.8 b
166.6 c
0.0 a
558.2 b
172.3 c

NC
NC
0.0 a
494.5 b
167.6 c
0.0 a
509.8 b
163.7 c
0.0 a
512.6 b
160.2 c
0.0 a
514.2 b
161.0 c
0.0 a
497.0 b
159.7 c
0.0 a
528.3 b
0.0 a
530.8 b
162.0 c
0.0 a
492.6 b
164.6 c
0.0 a
531.6 b
162.5 c
0.0 a
504.6 b
161.3 c
  0.0 a
531.6 b
162.5 c
B3LYPultrafine         0.0 a
494.4 b
                       
B3PW91 0.0 a
186.5 b
202.4 c
0.0 a
364.5 b
167.5 c
0.0 a
364.5 b
167.5 c
0.0 a
494.7 b
173.9 c
0.0 a
431.5 b
169.6 c
0.0 a
431.6 b
169.3 c
0.0 a
443.2 b
165.6 c
0.0 a
444.7 b
162.2 c
0.0 a
446.1 b
163.3 c
0.0 a
431.6 b
    0.0 a
427.5 b
165.6 c
0.0 a
460.2 b
165.5 c
0.0 a
436.8 b
163.5 c
  0.0 a
460.2 b
165.5 c
mPW1PW91 0.0 a
170.6 b
204.0 c
0.0 a
351.1 b
167.5 c
0.0 a
344.8 b
167.6 c
0.0 a
483.1 b
181.0 c
0.0 a
418.6 b
169.8 c
0.0 a
418.7 b
169.7 c
0.0 a
431.2 b
165.8 c
0.0 a
437.8 b
169.0 c
0.0 a
433.2 b
163.8 c
0.0 a
419.0 b
    0.0 a
415.4 b
166.0 c
0.0 a
453.7 b
172.4 c
0.0 a
424.5 b
  0.0 a
453.7 b
172.4 c
M06-2X         0.0 a
446.6 b
162.8 c
                       
PBEPBE 0.0 a
204.2 b
197.7 c
0.0 a
351.3 b
162.9 c
0.0 a
351.3 b
162.8 c
0.0 a
487.1 b
169.0 c
0.0 a
427.6 b
165.6 c
0.0 a
427.4 b
165.2 c
0.0 a
439.5 b
160.7 c
0.0 a
438.7 b
157.7 c
0.0 a
439.6 b
158.5 c
0.0 a
424.2 b
158.2 c
0.0 a
450.2 b
158.9 c
  0.0 a
420.1 b
161.6 c
0.0 a
453.7 b
160.8 c
0.0 a
431.2 b
  0.0 a
453.7 b
160.8 c
PBEPBEultrafine         0.0 a
427.5 b
                       
PBE1PBE         0.0 a
407.4 b
169.7 c
                       
HSEh1PBE         0.0 a
420.2 b
169.3 c
                       
TPSSh             0.0 a
442.1 b
166.0 c
                   
Moller Plesset perturbation MP2 0.0 a
278.5 b
187.4 c
0.0 a
473.2 b
159.1 c
0.0 a
473.2 b
159.1 c
0.0 a
590.8 b
162.2 c
0.0 a
471.7 b
174.0 c
0.0 a
470.8 b
174.3 c
0.0 a
492.9 b
168.5 c
0.0 a
462.1 b
168.3 c
0.0 a
458.4 b
168.9 c
0.0 a
432.6 b
  0.0 a
490.0 b
154.4 c
0.0 a
458.6 b
172.7 c
       
MP2=FULL   0.0 a
472.2 b
159.3 c

NC
NC
0.0 a
589.1 b
162.5 c
0.0 a
465.0 b
174.6 c
0.0 a
463.6 b
174.9 c
0.0 a
485.9 b
169.1 c
0.0 a
457.8 b
168.7 c
0.0 a
453.6 b
169.4 c
      0.0 a
458.0 b
173.2 c
       
MP3         0.0 a
459.8 b
                       
MP3=FULL         0.0 a
452.8 b
153.2 c
  0.0 a
473.8 b
149.8 c
                   
B2PLYP         0.0 a
488.9 b
168.3 c
                0.0 a
512.5 b
164.5 c
     
Configuration interaction CID        
NC
NC
                       
CISD        
NC
NC
                       
Quadratic configuration interaction QCISD   0.0 a
444.7 b
                             

Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 0.0 a
534.5 b
180.6 c
0.0 a
428.5 b
167.1 c
0.0 a
553.1 b
173.2 c
0.0 a
485.1 b
158.6 c
0.0 a
582.8 b
176.6 c
0.0 a
579.8 b
176.7 c
density functional B1B95 0.0 a
382.6 b
181.6 c
0.0 a
305.5 b
176.7 c
       
B3LYP 0.0 a
478.5 b
178.8 c
0.0 a
417.4 b
173.7 c
0.0 a
513.3 b
171.0 c
0.0 a
470.5 b
164.9 c
0.0 a
522.5 b
175.5 c
0.0 a
522.5 b
175.5 c
Moller Plesset perturbation MP2 0.0 a
526.0 b
169.4 c
0.0 a
384.4 b
177.6 c
0.0 a
534.1 b
149.6 c
0.0 a
431.1 b
163.3 c
0.0 a
561.3 b
160.4 c
0.0 a
559.4 b
160.3 c

Single point energy calculations (select basis sets)
aug-cc-pVTZ
Moller Plesset perturbation MP2FC// MP2FC/6-31G* 0.0 a
468.6 b
172.7 c
Coupled Cluster CCSD// MP2FC/6-31G* 0.0 a
454.2 b
147.3 c
CCSD(T)// MP2FC/6-31G*
NC
NC
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.