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

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

Isomers of C8H10

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a CH3C6H4CH3 106423 paraxylene   sketch of paraxylene
b CH3C6H4CH3 108383 meta-xylene 0.0 sketch of meta-xylene
c C6H5CH2CH3 100414 Ethylbenzene 12.6 sketch of Ethylbenzene
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
semi-empirical AM1 423.3 a
35.6 c
PM3 408.3 a
428.5 c
PM6 3.7 a
0.0 b
composite G1
NC
G2MP2
NC
G2
NC
G3 NC
NC
G3B3 409.8 a
0.0 b
426.7 c
G3MP2
NC
G4
0.0 b
18.0 c
CBS-Q NC

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 aug-cc-pVTZ cc-pV(T+d)Z
hartree fock HF
NC

NC

NC

NC
 
NC

NC

NC

NC
 
NC

NC

NC

NC

NC

NC
density functional LSDA
NC

NC

NC

NC

NC

NC

NC

NC

NC

NC
 
NC

NC

NC
 
NC
BLYP
NC

NC

NC

NC

NC

NC

NC

NC

NC
   
NC

NC

NC
 
NC
B1B95
NC

NC

NC

NC

NC

NC

NC

NC

NC

NC
 
NC

NC

NC
 
NC
B3LYP
NC

NC

NC

NC

NC

NC

NC

NC

NC
   
NC
 
NC
   
B3LYPultrafine        
NC
                     
B3PW91
NC

NC

NC

NC

NC

NC

NC

NC

NC
   
NC

NC

NC
 
NC
mPW1PW91
NC

NC

NC

NC

NC

NC

NC

NC

NC
   
NC

NC
   
NC
PBEPBE
NC

NC

NC

NC

NC

NC

NC

NC

NC
 
NC

NC

NC
   
NC
Moller Plesset perturbation MP2
NC

NC

NC

NC
 
NC

NC

NC

NC
   
NC
 
NC
 
NC
MP2=FULL
NC

NC

NC

NC
 
NC

NC

NC

NC
   
NC
     
NC
MP3        
NC
                     
Configuration interaction CID        
NC
                     
CISD        
NC
                     
Quadratic configuration interaction QCISD  
NC
 
NC

NC
                     
Coupled Cluster CCD  
NC
 
NC

NC
                     

Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF
NC

NC

NC

NC

NC

NC
density functional B1B95
NC

NC
       
B3LYP
NC

NC

NC

NC

NC

NC
Moller Plesset perturbation MP2
NC

NC

NC

NC

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.