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

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

Isomers of CH4O2

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a H2OH2CO 55 water formaldehyde dimer   sketch of water formaldehyde dimer
b CH2(OH)2 463570 methanediol   sketch of methanediol
c CH3OOH 3031730 Methyl peroxide 0.0 sketch of Methyl peroxide
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
semi-empirical AM1
-203.9 b
0.0 c
PM3 -229.0 a
-263.0 b
0.0 c
PM6 -247.5 a
-313.1 b
0.0 c
composite G1 -416.4 a
-570.8 b
0.0 c
G2MP2 -421.1 a
-574.8 b
0.0 c
G2 -420.4 a
-575.0 b
0.0 c
G3
-574.4 b
0.0 c
G3B3 NC
NC
0.0 c
G3MP2 -421.9 a
0.0 c
G4 -244.1 a
-258.5 b
0.0 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) 6-311+G(3df,2pd) cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z
hartree fock HF 60.6 a
0.0 c
-160.7 a
0.0 c

0.0 c

0.0 c
 
0.0 c
 
0.0 c

0.0 c
 
0.0 c
NC
0.0 c

0.0 c

0.0 c

0.0 c
-266.5 a
0.0 c

0.0 c
density functional LSDA
0.0 c
-121.9 a
0.0 c
-121.9 a
0.0 c
-155.8 a
0.0 c
-161.0 a
0.0 c
-172.4 a
0.0 c
-188.7 a
0.0 c
-177.5 a
0.0 c
-193.3 a
0.0 c
-174.3 a
0.0 c
    -177.4 a
0.0 c
-189.2 a
0.0 c
 
0.0 c
  -189.2 a
0.0 c
BLYP
0.0 c

0.0 c

0.0 c

0.0 c

0.0 c

0.0 c

0.0 c

0.0 c
       
0.0 c

0.0 c
 
0.0 c
 
0.0 c
B1B95 41.7 a
0.0 c
-134.2 a
0.0 c
-134.2 a
0.0 c
-180.0 a
0.0 c
-196.6 a
0.0 c
-207.7 a
0.0 c

0.0 c
-209.1 a
0.0 c
-224.6 a
0.0 c
-210.7 a
0.0 c
    -211.9 a
0.0 c
-223.2 a
0.0 c
  -228.4 a
0.0 c
  -223.2 a
0.0 c
B3LYP
0.0 c
-135.0 a
0.0 c

0.0 c

0.0 c
-195.7 a
0.0 c

0.0 c
-224.8 a
0.0 c

0.0 c

0.0 c
    NC
0.0 c

0.0 c
    -231.4 a
0.0 c

0.0 c
B3LYPultrafine   NC     NC   NC         NC           a  
B3PW91
0.0 c

0.0 c

0.0 c

0.0 c

0.0 c

0.0 c

0.0 c

0.0 c

0.0 c
     
0.0 c

0.0 c
 
0.0 c
 
0.0 c
mPW1PW91
0.0 c

0.0 c

0.0 c

0.0 c

0.0 c

0.0 c

0.0 c

0.0 c

0.0 c
     
0.0 c

0.0 c
     
0.0 c
PBEPBE
0.0 c
NC
0.0 c
  NC   NC  
0.0 c
 
0.0 c
NC         -211.4 a
0.0 c
 
PBEPBEultrafine   NC       a   NC         NC         NC  
Moller Plesset perturbation MP2
0.0 c
-172.7 a
0.0 c

0.0 c

0.0 c
  a
0.0 c
  a
0.0 c

0.0 c
    NC
0.0 c

0.0 c
 
0.0 c
NC
0.0 c
MP2=FULL  
0.0 c

0.0 c

0.0 c

0.0 c

0.0 c

0.0 c

0.0 c

0.0 c
     
0.0 c

0.0 c
     
0.0 c
MP4  
0.0 c
   
0.0 c
                         
Configuration interaction CID        
0.0 c
                         
CISD        
0.0 c
                         
Quadratic configuration interaction QCISD  
0.0 c

0.0 c

0.0 c

0.0 c

0.0 c
 
0.0 c
        -239.7 a
0.0 c
         
Coupled Cluster CCD  
0.0 c

0.0 c

0.0 c

0.0 c

0.0 c
 
0.0 c
        -236.6 a
0.0 c
         
CCSD(T)   NC       a   NC                      

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

0.0 c

0.0 c
-244.7 a
0.0 c
-216.4 a
0.0 c

0.0 c
density functional B1B95
0.0 c
-197.0 a
0.0 c
       
B3LYP
0.0 c

0.0 c

0.0 c
-201.4 a
0.0 c

0.0 c

0.0 c
B3LYPultrafine         NC  
Moller Plesset perturbation MP2
0.0 c

0.0 c

0.0 c
-233.9 a
0.0 c
-221.8 a
0.0 c

0.0 c

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* -426.5 a
0.0 c
  -418.8 a
0.0 c
  -418.8 a
0.0 c
MP2FC// B3LYP/6-31G* -254.1 a
0.0 c
-248.1 a
0.0 c
-247.0 a
0.0 c
  -247.0 a
0.0 c
MP2FC// MP2FC/6-31G*     -247.5 a
0.0 c
-257.0 a
0.0 c
-247.5 a
0.0 c
MP4// HF/6-31G* -416.1 a
0.0 c
  -410.1 a
0.0 c
  -410.1 a
0.0 c
MP4// B3LYP/6-31G*   -238.9 a
0.0 c
-237.2 a
0.0 c
  -237.2 a
0.0 c
MP4// MP2/6-31G*     -237.8 a
0.0 c
  -237.8 a
0.0 c
Coupled Cluster CCSD// B3LYP/6-31G* -243.0 a
0.0 c
       
CCSD(T)// B3LYP/6-31G* -239.4 a
0.0 c
       
CCSD// MP2FC/6-31G*       -245.1 a
0.0 c
 
CCSD(T)// MP2FC/6-31G*       -241.7 a
0.0 c
 
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.