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

Isomers of CH3O

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a CH3O+ 2143682 Methoxy cation   sketch of Methoxy cation
b CH2OH+ 2597435 hydroxymethyl cation   sketch of hydroxymethyl cation
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
semi-empirical AM1 1025.7 a
771.6 b
PM3 1028.4 a
792.5 b
PM6 952.5 a
789.4 b
composite G1 NC
NC
G2MP2 NC
NC
G2 NC
NC
G3 NC
NC
G3B3 NC
NC
G3MP2
NC
G4 NC
NC
CBS-Q 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) 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
B1B95
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

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
   
NC
PBEPBE
NC

NC

NC

NC

NC

NC

NC

NC

NC

NC

NC

NC
   
NC
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z
Moller Plesset perturbation MP2
NC

NC

NC

NC
 
NC

NC
 
NC

NC

NC

NC

NC

NC

NC
MP2=FULL
NC

NC

NC

NC

NC

NC

NC

NC

NC

NC

NC

NC
   
NC
MP3        
NC
                   
MP4  
NC
   
NC
     
NC
           
Configuration interaction CID  
NC

NC

NC

NC
   
NC
             
CISD  
NC

NC

NC

NC
   
NC
             
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z
Quadratic configuration interaction QCISD  
NC

NC

NC

NC

NC

NC

NC

NC

NC

NC

NC
   
NC
QCISD(T)        
NC
         
NC

NC

NC

NC

NC
Coupled Cluster CCD  
NC

NC

NC

NC

NC

NC

NC

NC

NC

NC

NC

NC

NC

NC
CCSD        
NC
                   
CCSD(T)        
NC
         
NC

NC

NC

NC

NC
CCSD(T)=FULL        
NC
                   
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ 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
-59085.5 b

-59241.6 b

-59094.1 b

-59253.8 b

NC

NC
density functional B3LYP
-60375.5 b

-60484.7 b

-60384.7 b

-60497.5 b

NC

NC
Moller Plesset perturbation MP2
-59556.8 b

-59967.2 b

-59622.1 b

-60028.5 b

NC

NC

Single point energy calculations (select basis sets)
cc-pVTZ cc-pV(T+d)Z
Coupled Cluster CCSD(T)//B3LYP/6-31G(2df,p)
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 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.