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

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

Isomers of CH6O2

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a H2OCH3OH 77 water methanol dimer   sketch of water methanol dimer
b CH3OHH2O 88 methanol water dimer   sketch of methanol water dimer
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
semi-empirical PM3 -263.7 a
-264.8 b
PM6 -287.2 a
2053.2 b
composite G1 NC
NC
G2MP2 NC
NC
G2 NC
NC
G3B3 NC
NC
G3MP2 NC
NC
G4 NC
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) 6-311+G(3df,2pd) 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
 
density functional LSDA NC
NC
NC
NC
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
NC
NC
NC
NC
NC
NC
    NC
NC

NC

NC
 
NC
B3LYP   NC
NC
    NC
NC
  NC
NC
        NC
NC
      NC
NC
 
B3LYPultrafine   NC
NC
    NC
NC
  NC
NC
        NC
NC
      NC
NC
 
mPW1PW91
NC
                               
PBEPBE   NC
NC
    NC
NC
  NC
NC
        NC
NC
      NC
NC
 
PBEPBEultrafine   NC
NC
    NC
NC
  NC
NC
        NC
NC
      NC
NC
 
Moller Plesset perturbation MP2   NC
NC
   
NC
  NC
NC
        NC
NC
      NC  
Quadratic configuration interaction QCISD                         NC
NC
       
Coupled Cluster CCD                         NC
NC
       
CCSD(T)   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  
density functional B1B95 NC NC
NC
       
B3LYP       NC NC  
Moller Plesset perturbation MP2       NC NC  

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* NC
NC
  NC
NC
  NC
NC
MP2FC// B3LYP/6-31G* NC
NC
NC
NC
NC
NC
  NC
NC
MP2FC// MP2FC/6-31G*     NC
NC
NC
NC
NC
NC
MP4// HF/6-31G* NC
NC
  NC
NC
  NC
NC
MP4// B3LYP/6-31G*   NC
NC
NC
NC
  NC
NC
MP4// MP2/6-31G*     NC
NC
  NC
NC
Coupled Cluster CCSD// B3LYP/6-31G* NC
NC
       
CCSD(T)// B3LYP/6-31G* NC
NC
       
CCSD// MP2FC/6-31G*       NC
NC
 
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.