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

Relative enthalpies of isomers - Comparison of 0K enthalpies (kJ mol-1)

Isomers of C2H2O

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a C2H2O 157186 Oxirene   sketch of Oxirene
b CH2CO 463514 Ketene 0.0 sketch of Ketene
c HCCOH 32038792 ethynol   sketch of ethynol
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
composite G1
0.0 b
146.2 c
G2MP2
0.0 b
147.6 c
G2
0.0 b
147.2 c
G3
0.0 b
144.6 c
G3B3
0.0 b
140.1 c
G3MP2
0.0 b
144.4 c
CBS-Q 316.4 a
0.0 b
141.3 c

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) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z
hartree fock HF 266.9 a
0.0 b
89.4 c
382.5 a
0.0 b
132.2 c
382.5 a
0.0 b
132.3 c
358.4 a
0.0 b
132.2 c
  364.9 a
0.0 b
154.5 c
358.8 a
0.0 b
149.9 c
378.7 a
0.0 b
168.2 c
374.8 a
0.0 b
152.1 c
370.4 a
0.0 b
156.2 c

0.0 b
152.5 c
364.2 a
0.0 b
147.5 c
379.1 a
0.0 b
159.5 c
366.4 a
0.0 b
151.3 c

0.0 b
150.9 c
363.7 a
0.0 b
154.1 c

0.0 b
150.5 c

0.0 b
151.3 c
density functional LSDA
0.0 b
166.4 c

0.0 b
163.8 c

0.0 b
163.8 c

0.0 b
162.6 c

0.0 b
172.8 c

0.0 b
162.3 c

0.0 b
154.9 c

0.0 b
171.1 c

0.0 b
155.9 c

0.0 b
157.7 c
   
0.0 b
161.6 c

0.0 b
151.2 c
 
0.0 b
152.2 c
 
0.0 b
151.2 c
SVWN   372.7 a
0.0 b
163.8 c
    328.6 a
0.0 b
172.7 c
  317.3 a
0.0 b
154.9 c
                     
BLYP 286.6 a
0.0 b
166.5 c
362.0 a
0.0 b
171.3 c
362.0 a
0.0 b
171.3 c
327.8 a
0.0 b
169.5 c
333.2 a
0.0 b
181.2 c
332.1 a
0.0 b
170.9 c
321.8 a
0.0 b
162.8 c
346.4 a
0.0 b
177.7 c
342.9 a
0.0 b
163.8 c
336.1 a
0.0 b
166.4 c
    340.8 a
0.0 b
169.2 c
332.9 a
0.0 b
159.8 c
     
0.0 b
159.8 c
B1B95
0.0 b
150.8 c

0.0 b
158.9 c

0.0 b
158.9 c

0.0 b
157.4 c
 
0.0 b
162.9 c

0.0 b
156.8 c

0.0 b
173.7 c

0.0 b
158.5 c

0.0 b
159.6 c
   
0.0 b
164.0 c

0.0 b
154.1 c
 
0.0 b
155.3 c
 
0.0 b
154.1 c
B3LYP
0.0 b
150.8 c

0.0 b
161.7 c
367.6 a
0.0 b
161.7 c
334.6 a
0.0 b
159.8 c

0.0 b
175.9 c
337.5 a
0.0 b
165.1 c
317.3 a
0.0 b
158.0 c
351.8 a
0.0 b
173.5 c
348.3 a
0.0 b
158.9 c
342.0 a
0.0 b
  338.6 a
0.0 b
156.3 c
325.2 a
0.0 b
164.7 c
338.8 a
0.0 b
155.5 c
  329.8 a
0.0 b
156.0 c

0.0 b
153.6 c

0.0 b
155.5 c
B3LYPultrafine         338.5 a
0.0 b
175.9 c
 
0.0 b
158.0 c
           
0.0 b
155.5 c
       
B3PW91 284.4 a
0.0 b
155.3 c
367.8 a
0.0 b
161.8 c
367.8 a
0.0 b
161.8 c
334.9 a
0.0 b
160.6 c
335.6 a
0.0 b
176.4 c
334.6 a
0.0 b
165.2 c
326.3 a
0.0 b
159.3 c
347.6 a
0.0 b
175.8 c
344.0 a
0.0 b
160.4 c
337.8 a
0.0 b
162.0 c
    343.4 a
0.0 b
166.3 c
334.4 a
0.0 b
156.8 c
     
0.0 b
156.8 c
mPW1PW91 282.1 a
0.0 b
151.2 c
365.3 a
0.0 b
156.5 c
368.8 a
0.0 b
159.6 c
336.6 a
0.0 b
158.7 c
333.2 a
0.0 b
172.6 c
332.3 a
0.0 b
161.1 c
324.7 a
0.0 b
155.4 c
345.1 a
0.0 b
172.4 c
344.6 a
0.0 b
159.7 c
339.0 a
0.0 b
161.2 c
    341.0 a
0.0 b
162.7 c
332.7 a
0.0 b
153.3 c
     
0.0 b
153.3 c
M06-2X         325.1 a
0.0 b
158.1 c
                         
PBEPBE 288.6 a
0.0 b
171.9 c
362.6 a
0.0 b
172.1 c
362.6 a
0.0 b
172.1 c
329.5 a
0.0 b
171.1 c
329.8 a
0.0 b
182.1 c
328.6 a
0.0 b
171.2 c
318.7 a
0.0 b
164.2 c
341.7 a
0.0 b
180.6 c
338.0 a
0.0 b
165.6 c
330.7 a
0.0 b
167.1 c
    337.0 a
0.0 b
171.0 c
327.0 a
0.0 b
160.8 c
   
0.0 b
158.6 c

0.0 b
160.8 c
PBEPBEultrafine         329.8 a
0.0 b
182.1 c
                         
PBE1PBE         336.0 a
0.0 b
175.9 c
                         
HSEh1PBE         336.2 a
0.0 b
175.9 c
                         
TPSSh             315.4 a
0.0 b
166.3 c
                     
Moller Plesset perturbation MP2 293.1 a
0.0 b
111.0 c
370.9 a
0.0 b
146.1 c
370.9 a
0.0 b
146.1 c
330.4 a
0.0 b
140.3 c
NC
NC
330.6 a
0.0 b
152.3 c
 
0.0 b
165.1 c
346.3 a
0.0 b
147.0 c
335.9 a
0.0 b
147.1 c
  332.1 a
0.0 b
145.8 c
352.5 a
0.0 b
155.0 c
330.4 a
0.0 b
141.4 c
  325.4 a
0.0 b
146.8 c
 
0.0 b
141.4 c
MP2=FULL NC
NC
370.8 a
0.0 b
146.0 c
NC
NC
NC
NC
NC
NC
332.3 a
0.0 b
152.6 c
321.8 a
0.0 b
147.5 c
348.9 a
0.0 b
164.9 c
347.0 a
0.0 b
146.8 c
NC
NC
    353.2 a
0.0 b
155.2 c
332.5 a
0.0 b
141.6 c
       
MP3         320.7 a
0.0 b
                         
MP3=FULL         322.3 a
0.0 b
152.8 c
  316.2 a
0.0 b
141.2 c
                     
MP4 NC
NC
NC
NC
    330.7 a
0.0 b
169.4 c
      NC
NC
NC
NC
               
B2PLYP         336.8 a
0.0 b
170.9 c
                336.6 a
0.0 b
151.3 c
       
Configuration interaction CID   NC
NC
    335.4 a
0.0 b
159.3 c
        NC
NC
               
CISD   NC
NC
    337.1 a
0.0 b
161.7 c
                         
Quadratic configuration interaction QCISD NC
NC
349.7 a
0.0 b
137.4 c
  NC
NC
326.3 a
0.0 b
159.5 c
327.4 a
0.0 b
152.0 c
318.2 a
0.0 b
146.6 c
344.5 a
0.0 b
165.3 c
342.7 a
0.0 b
148.3 c
NC
NC
    348.1 a
0.0 b
156.9 c
NC
NC
       
QCISD(T)         319.6 a
0.0 b
160.0 c
      NC
NC
        NC
NC
       
Coupled Cluster CCD NC
NC
NC
NC
  NC
NC
322.1 a
0.0 b
152.9 c
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
    346.0 a
0.0 b
150.3 c
NC
NC
       
CCSD         323.7 a
0.0 b
155.8 c
      NC
NC
        NC
NC
       
CCSD(T)         319.0 a
0.0 b
159.0 c
      NC
NC
        NC
NC
       

Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 336.7 a
0.0 b
139.9 c
346.9 a
0.0 b
181.7 c
338.3 a
0.0 b
118.0 c
351.8 a
0.0 b
157.4 c
354.5 a
0.0 b
119.4 c
354.7 a
0.0 b
119.0 c
density functional B1B95
0.0 b
157.5 c

0.0 b
178.5 c
       
B3LYP 309.1 a
0.0 b
162.0 c
318.4 a
0.0 b
183.4 c
311.7 a
0.0 b
147.3 c
322.8 a
0.0 b
166.2 c
330.0 a
0.0 b
147.8 c
330.4 a
0.0 b
148.3 c
Moller Plesset perturbation MP2 309.3 a
0.0 b
145.3 c
314.3 a
0.0 b
172.4 c
310.1 a
0.0 b
131.2 c
314.6 a
0.0 b
156.4 c
327.3 a
0.0 b
129.4 c
327.2 a
0.0 b
129.5 c

Single point energy calculations (select basis sets)
6-311+G(3df,2p) cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z
Moller Plesset perturbation MP2FC// HF/6-31G*
0.0 b
146.3 c
 
0.0 b
144.9 c
   
0.0 b
144.9 c
MP2FC// B3LYP/6-31G*
0.0 b
142.2 c

0.0 b
156.5 c

0.0 b
140.9 c
   
0.0 b
140.9 c
MP2FC// MP2FC/6-31G*    
0.0 b
138.6 c

0.0 b
146.0 c

0.0 b
137.8 c

0.0 b
138.6 c
MP4// HF/6-31G*
0.0 b
154.4 c
 
0.0 b
152.5 c
   
0.0 b
152.5 c
MP4// B3LYP/6-31G*  
0.0 b
166.6 c

0.0 b
150.0 c
   
0.0 b
150.0 c
MP4// MP2/6-31G*    
0.0 b
148.1 c
   
0.0 b
148.1 c
Coupled Cluster CCSD// B3LYP/6-31G*
0.0 b
141.3 c
         
CCSD(T)// B3LYP/6-31G*
0.0 b
143.9 c
 
0.0 b
142.0 c
     
CCSD// MP2FC/6-31G*      
0.0 b
144.2 c

0.0 b
136.5 c
 
CCSD(T)// MP2FC/6-31G*      
0.0 b
147.0 c

0.0 b
138.8 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.