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

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

Isomers of C2H4O2

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a CHOCH2OH 141468 hydroxy acetaldehyde   sketch of hydroxy acetaldehyde
b C2H4O2 61233190 1,3-dioxetane   sketch of 1,3-dioxetane
c CH3COOH 64197 Acetic acid 0.0 sketch of Acetic acid
d CH3OCHO 107313 methyl formate 79.9 sketch of methyl formate
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
semi-empirical AM1 -209.2 a
-381.2 d
PM3 74.8 a
0.0 c
57.4 d
PM6 115.3 a
200.5 b
0.0 c
72.5 d
MNDOd
0.0 c
65.2 d
composite G1 112.5 a
-117.7 b
0.0 c
73.1 d
G2MP2 109.0 a
-122.0 b
0.0 c
72.4 d
G2 109.7 a
-120.6 b
0.0 c
72.9 d
G3 110.9 a
-115.7 b
0.0 c
75.5 d
G3B3 111.2 a
230.8 b
0.0 c
70.7 d
G3MP2 109.8 a
-115.8 b
0.0 c
75.8 d
G4 111.6 a
227.2 b
0.0 c
69.9 d
CBS-Q 112.3 a
232.7 b
0.0 c
70.7 d
molecular mechanics DREIDING
0.0 c
MM3
0.0 c
-54.9 d

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 98.6 a
0.0 c
28.0 d
129.6 a
0.0 c
54.5 d
129.6 a
0.0 c
54.5 d
116.5 a
0.0 c
75.5 d
  123.5 a
0.0 c
70.2 d
  123.5 a
0.0 c
57.8 d
120.9 a
0.0 c
70.9 d
121.8 a
0.0 c
68.0 d
116.6 a
0.0 c
67.7 d
121.5 a
0.0 c
71.3 d
118.4 a
0.0 c
69.0 d
112.6 a
0.0 c
74.6 d
116.1 a
0.0 c
68.8 d
118.4 a
0.0 c
69.0 d
density functional LSDA 117.9 a
0.0 c
7.0 d
131.2 a
0.0 c
52.5 d
131.2 a
0.0 c
52.5 d
124.9 a
0.0 c
69.6 d
121.6 a
0.0 c
57.0 d
120.8 a
0.0 c
67.8 d
118.0 a
0.0 c
74.2 d
126.1 a
0.0 c
62.1 d
122.9 a
0.0 c
75.1 d
117.4 a
0.0 c
66.3 d
  118.8 a
0.0 c
71.5 d
117.9 a
0.0 c
74.5 d
111.4 a
0.0 c
77.1 d
  117.9 a
0.0 c
74.5 d
BLYP 118.8 a
0.0 c
5.9 d
124.6 a
0.0 c
37.0 d
124.6 a
0.0 c
37.0 d
116.7 a
0.0 c
52.6 d
115.6 a
0.0 c
44.3 d
115.3 a
0.0 c
54.6 d
111.8 a
0.0 c
61.4 d
  a
  d
117.7 a
0.0 c
61.6 d
112.8 a
0.0 c
53.7 d
  114.0 a
0.0 c
58.4 d
113.6 a
0.0 c

0.0 c
65.6 d
  113.6 a
0.0 c
B1B95 118.7 a
0.0 c
18.7 d
140.1 a
0.0 c
50.8 d
140.1 a
0.0 c
50.8 d
132.8 a
0.0 c
66.9 d
121.2 a
0.0 c
55.2 d
130.9 a
0.0 c
65.9 d
127.9 a
0.0 c
70.3 d
134.6 a
0.0 c
57.5 d
131.9 a
0.0 c
70.5 d

0.0 c
64.7 d
  128.5 a
0.0 c
69.1 d
116.9 a
0.0 c
69.9 d

0.0 c
74.6 d
  116.9 a
0.0 c
69.9 d
B3LYP 113.5 a
0.0 c
12.8 d
126.6 a
0.0 c
45.8 d
126.6 a
0.0 c
45.8 d
117.4 a
0.0 c
61.7 d
118.4 a
0.0 c
50.4 d
118.1 a
0.0 c
61.3 d
114.1 a
0.0 c
66.7 d
121.6 a
0.0 c
54.7 d
119.2 a
0.0 c
66.9 d
115.6 a
0.0 c
60.0 d

0.0 c
66.0 d
116.5 a
0.0 c
115.4 a
0.0 c
66.1 d
109.0 a
0.0 c
88.8 d
112.3 a
0.0 c
66.9 d
115.4 a
0.0 c
66.1 d
B3LYPultrafine         118.4 a
0.0 c
50.4 d
                     
B3PW91 118.3 a
0.0 c
19.1 d
131.2 a
0.0 c
54.2 d
131.2 a
0.0 c
54.2 d
121.0 a
0.0 c
68.5 d
122.1 a
0.0 c
56.7 d
121.6 a
0.0 c
67.9 d
117.4 a
0.0 c
71.9 d
123.8 a
0.0 c
59.3 d
121.3 a
0.0 c
72.2 d
118.8 a
0.0 c
66.6 d
  119.5 a
0.0 c
70.3 d
117.5 a
0.0 c
71.4 d

0.0 c
75.0 d
  117.5 a
0.0 c
71.4 d
mPW1PW91 116.4 a
0.0 c
20.6 d
126.9 a
0.0 c
55.3 d
131.3 a
0.0 c
55.4 d
121.0 a
0.0 c
70.2 d
118.6 a
0.0 c
57.7 d
118.2 a
0.0 c
69.2 d
114.2 a
0.0 c
73.2 d
120.2 a
0.0 c
60.0 d
121.5 a
0.0 c
73.3 d
119.2 a
0.0 c
67.8 d
  115.8 a
0.0 c
71.4 d
114.0 a
0.0 c
72.5 d

0.0 c
76.2 d
  114.0 a
0.0 c
72.5 d
PBEPBE 123.1 a
0.0 c
13.0 d
129.0 a
0.0 c
47.6 d
129.0 a
0.0 c
47.6 d
121.2 a
0.0 c
62.1 d
119.9 a
0.0 c
52.6 d
119.4 a
0.0 c
63.4 d
115.9 a
0.0 c
69.3 d
123.1 a
0.0 c
56.8 d
120.5 a
0.0 c
69.3 d
116.3 a
0.0 c
62.4 d

0.0 c
69.1 d
117.5 a
0.0 c
82.9 d
116.3 a
0.0 c
69.0 d

0.0 c
72.6 d
113.2 a
0.0 c
70.0 d
116.3 a
0.0 c
69.0 d
Moller Plesset perturbation MP2 103.7 a
0.0 c
17.6 d
129.2 a
0.0 c
49.1 d
  a
  d
120.0 a
0.0 c
69.4 d
  124.4 a
0.0 c
67.8 d
  130.2 a
0.0 c
62.0 d
123.5 a
0.0 c
75.3 d
124.3 a
0.0 c
69.2 d
  123.8 a
0.0 c
73.4 d
  113.4 a
0.0 c
75.7 d
  119.7 a
0.0 c
73.1 d
MP2=FULL NC 129.2 a
0.0 c
49.1 d
NC NC   125.0 a
0.0 c
67.9 d
119.8 a
0.0 c
71.2 d
130.7 a
0.0 c
62.8 d
123.9 a
0.0 c
75.9 d
NC   124.1 a
0.0 c
73.4 d
      NC
MP3        
0.0 c
63.1 d
                     
MP4   NC     122.1 a
0.0 c
55.7 d
                     
Configuration interaction CID   NC NC NC 123.1 a
0.0 c
85.9 d
    NC                
CISD   NC NC NC 123.5 a
0.0 c
85.0 d
    NC                
Quadratic configuration interaction QCISD NC 120.2 a
0.0 c
71.5 d
NC NC 119.6 a
0.0 c
83.8 d
117.8 a
0.0 c
64.9 d
113.0 a
0.0 c
67.8 d
123.5 a
0.0 c
59.9 d
116.7 a
0.0 c
71.0 d
NC   NC        
QCISD(T)         NC   NC   NC              
Coupled Cluster CCD NC NC NC NC 118.5 a
0.0 c
85.2 d
NC NC NC NC NC   NC        
CCSD         NC   NC   NC              
CCSD(T)         NC   NC   NC              

Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 102.9 a
0.0 c
71.6 d
116.4 a
0.0 c
55.0 d
102.3 a
0.0 c
74.2 d
116.0 a
0.0 c
59.1 d
106.1 a
0.0 c
77.8 d
106.4 a
0.0 c
78.0 d
density functional B1B95 112.1 a
0.0 c
66.2 d
118.9 a
0.0 c
56.3 d
       
B3LYP 107.3 a
0.0 c
60.4 d
113.5 a
0.0 c
51.0 d
104.7 a
0.0 c
61.4 d
111.9 a
0.0 c
54.4 d
110.0 a
0.0 c
66.4 d
110.3 a
0.0 c
66.2 d
Moller Plesset perturbation MP2 107.9 a
0.0 c
65.0 d
121.4 a
0.0 c
58.6 d
106.2 a
0.0 c
65.4 d
120.1 a
0.0 c
61.3 d
110.0 a
0.0 c
68.6 d
110.2 a
0.0 c
68.7 d

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* 116.5 a
0.0 c
76.4 d

0.0 c
79.9 d
117.9 a
0.0 c
78.0 d

0.0 c
79.5 d
117.9 a
0.0 c
78.0 d
MP2FC// B3LYP/6-31G*
0.0 c
123.5 a
0.0 c
74.1 d
118.8 a
0.0 c
73.1 d

0.0 c
76.2 d
118.8 a
0.0 c
73.1 d
MP2FC// MP2FC/6-31G*  
0.0 c
75.7 d
116.9 a
0.0 c
74.7 d
110.6 a
0.0 c
77.7 d
116.9 a
0.0 c
74.7 d
MP4// HF/6-31G* 113.1 a
0.0 c
72.4 d

0.0 c
76.5 d
114.2 a
0.0 c
74.5 d
  114.2 a
0.0 c
74.5 d
MP4// B3LYP/6-31G*   119.0 a
0.0 c
69.0 d
115.4 a
0.0 c
69.2 d
  115.4 a
0.0 c
69.2 d
MP4// MP2/6-31G*     113.3 a
0.0 c
70.6 d
  113.3 a
0.0 c
70.6 d
Coupled Cluster CCSD// HF/6-31G*  
0.0 c
76.5 d

0.0 c
75.8 d
 
0.0 c
75.8 d
CCSD(T)// HF/6-31G*  
0.0 c
75.4 d

0.0 c
75.1 d
 
0.0 c
75.1 d
CCSD// B3LYP/6-31G*
0.0 c

0.0 c
70.5 d
     
CCSD(T)// B3LYP/6-31G*
0.0 c

0.0 c
69.3 d
     
CCSD(T)//B3LYP/6-31G(2df,p)     113.8 a
0.0 c
69.4 d
  113.8 a
0.0 c
69.4 d
CCSD// MP2FC/6-31G*  
0.0 c
72.1 d

0.0 c
72.3 d
104.0 a
0.0 c
74.5 d

0.0 c
72.3 d
CCSD(T)// MP2FC/6-31G*  
0.0 c
70.7 d

0.0 c
71.3 d
104.8 a
0.0 c
73.3 d

0.0 c
71.3 d
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.