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

Relative enthalpies of isomers - Comparison of 298.15K 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 HCCOH 32038792 ethynol   sketch of ethynol
c CH2CO 463514 Ketene 0.0 sketch of Ketene
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
semi-empirical AM1 376.0 a
184.7 b
0.0 c
PM3 257.9 a
101.2 b
0.0 c
PM6 295.5 a
173.3 b
0.0 c
MNDOd
0.0 c
composite G1
146.7 b
0.0 c
G2MP2
148.1 b
0.0 c
G2 314.4 a
148.5 b
0.0 c
G3 318.7 a
145.1 b
0.0 c
G3B3
141.1 b
0.0 c
G3MP2
144.8 b
0.0 c
CBS-Q 316.5 a
141.8 b
0.0 c
molecular mechanics MM3
0.0 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) cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z
hartree fock HF
89.7 b
0.0 c
132.5 b
0.0 c
132.5 b
0.0 c
132.8 b
0.0 c
167.5 b
0.0 c
154.9 b
0.0 c 		 
168.6 b
0.0 c
152.4 b
0.0 c
156.5 b
0.0 c
152.9 b
0.0 c
159.9 b
0.0 c
151.7 b
0.0 c
151.3 b
0.0 c
154.6 b
0.0 c
150.9 b
0.0 c
151.7 b
0.0 c
density functional LSDA
167.1 b
0.0 c
164.2 b
0.0 c
164.2 b
0.0 c
163.5 b
0.0 c
173.8 b
0.0 c
163.3 b
0.0 c
155.8 b
0.0 c
172.0 b
0.0 c
156.5 b
0.0 c
158.6 b
0.0 c 		 
162.3 b
0.0 c
151.9 b
0.0 c 		 
153.1 b
0.0 c 		 
151.9 b
0.0 c
BLYP
167.5 b
0.0 c
171.7 b
0.0 c
171.7 b
0.0 c
170.8 b
0.0 c
182.5 b
0.0 c
172.1 b
0.0 c
163.9 b
0.0 c
178.8 b
0.0 c
164.8 b
0.0 c
167.7 b
0.0 c 		 
170.0 b
0.0 c
160.7 b
0.0 c 		 
0.0 c 		 
160.7 b
0.0 c
B1B95
151.3 b
0.0 c
159.2 b
0.0 c
159.2 b
0.0 c
158.3 b
0.0 c
0.0 c
163.7 b
0.0 c
157.6 b
0.0 c
174.4 b
0.0 c
159.1 b
0.0 c
160.3 b
0.0 c 		 
164.6 b
0.0 c
154.7 b
0.0 c 		 
156.2 b
0.0 c 		 
154.7 b
0.0 c
B3LYP
151.4 b
0.0 c
162.0 b
0.0 c
162.1 b
0.0 c
160.8 b
0.0 c
176.9 b
0.0 c
166.0 b
0.0 c
158.8 b
0.0 c
174.3 b
0.0 c
159.6 b
0.0 c
0.0 c
0.0 c
165.4 b
0.0 c
156.2 b
0.0 c 		 
157.0 b
0.0 c
154.3 b
0.0 c
156.2 b
0.0 c
B3LYPultrafine        
176.9 b
0.0 c 		                       
B3PW91
155.9 b
0.0 c
162.2 b
0.0 c
162.2 b
0.0 c
161.5 b
0.0 c
177.3 b
0.0 c
166.0 b
0.0 c
160.1 b
0.0 c
176.5 b
0.0 c
161.1 b
0.0 c
162.7 b
0.0 c 		 
166.9 b
0.0 c
157.5 b
0.0 c 		 
0.0 c 		 
157.5 b
0.0 c
mPW1PW91
151.8 b
0.0 c
156.8 b
0.0 c
159.9 b
0.0 c
159.5 b
0.0 c
173.5 b
0.0 c
161.9 b
0.0 c
156.1 b
0.0 c
173.2 b
0.0 c
160.3 b
0.0 c
161.9 b
0.0 c 		 
163.3 b
0.0 c
153.9 b
0.0 c 		 
0.0 c 		 
153.9 b
0.0 c
PBEPBE
172.7 b
0.0 c
172.4 b
0.0 c
172.5 b
0.0 c
172.3 b
0.0 c
183.4 b
0.0 c
172.4 b
0.0 c
165.2 b
0.0 c
181.6 b
0.0 c
166.5 b
0.0 c
168.2 b
0.0 c
0.0 c
171.9 b
0.0 c
161.7 b
0.0 c 		 
0.0 c
159.5 b
0.0 c
161.7 b
0.0 c
PBEPBEultrafine        
183.4 b
0.0 c 		                       
Moller Plesset perturbation MP2FC
111.5 b
0.0 c
146.9 b
0.0 c
146.9 b
0.0 c
142.3 b
0.0 c 		 
153.6 b
0.0 c
148.3 b
0.0 c
166.2 b
0.0 c
147.7 b
0.0 c
148.1 b
0.0 c 		 
155.9 b
0.0 c
142.3 b
0.0 c 		 
148.2 b
0.0 c 		 
142.3 b
0.0 c
MP2FU
NC
146.8 b
0.0 c
NC
NC
161.5 b
0.0 c
153.7 b
0.0 c
148.6 b
0.0 c
166.0 b
0.0 c
147.5 b
0.0 c
NC		  
156.0 b
0.0 c
NC		      
NC
MP3        
0.0 c 		                       
MP4
NC
NC		    
171.3 b
0.0 c 		     
NC
NC		              
Configuration interaction CID  
NC		    
160.2 b
0.0 c 		       
NC		              
CISD  
  b 		   
162.7 b
0.0 c 		                       
Quadratic configuration interaction QCISD
NC
138.2 b
0.0 c 		 
NC
160.9 b
0.0 c
153.3 b
0.0 c
147.9 b
0.0 c
166.4 b
0.0 c
149.0 b
0.0 c
NC		  
157.7 b
0.0 c
NC		      
NC
QCISD(T)        
161.9 b
0.0 c 		     
NC		      
NC		      
NC
Coupled Cluster CCD
NC
NC		  
NC
154.2 b
0.0 c
NC
NC
NC
NC
NC		  
151.1 b
0.0 c
NC		      
NC
CCSD        
157.2 b
0.0 c 		     
NC		      
NC		      
NC
CCSD(T)        
160.8 b
0.0 c
0.0 c 		   
NC		      
NC		      
NC
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF
140.4 b
0.0 c
182.0 b
0.0 c
118.5 b
0.0 c
157.7 b
0.0 c
120.0 b
0.0 c
119.5 b
0.0 c
density functional B1B95
158.1 b
0.0 c
179.1 b
0.0 c 		       
B3LYP
162.8 b
0.0 c
184.1 b
0.0 c
148.1 b
0.0 c
167.0 b
0.0 c
148.6 b
0.0 c
149.1 b
0.0 c
Moller Plesset perturbation MP2FC
146.2 b
0.0 c
172.9 b
0.0 c
132.3 b
0.0 c
157.2 b
0.0 c
130.4 b
0.0 c
130.4 b
0.0 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*
146.8 b
0.0 c
0.0 c
145.3 b
0.0 c
0.0 c
0.0 c
145.3 b
0.0 c
MP2FC// B3LYP/6-31G*
143.1 b
0.0 c
157.4 b
0.0 c
141.9 b
0.0 c
0.0 c
0.0 c
141.9 b
0.0 c
MP2FC// MP2FC/6-31G*
0.0 c
0.0 c
140.1 b
0.0 c
147.6 b
0.0 c 		 
140.1 b
0.0 c
MP4// HF/6-31G*
154.9 b
0.0 c
0.0 c
153.0 b
0.0 c 		   
153.0 b
0.0 c
MP4// B3LYP/6-31G*  
167.5 b
0.0 c
151.0 b
0.0 c 		   
151.0 b
0.0 c
MP4// MP2/6-31G*
0.0 c 		 
149.6 b
0.0 c 		   
149.6 b
0.0 c
Coupled Cluster CCSD// HF/6-31G*
0.0 c
0.0 c
0.0 c
0.0 c
0.0 c
0.0 c
CCSD(T)// HF/6-31G*
0.0 c
0.0 c
0.0 c
0.0 c
0.0 c
0.0 c
CCSD// B3LYP/6-31G*
142.3 b
0.0 c
0.0 c
0.0 c 		   
0.0 c
CCSD(T)// B3LYP/6-31G*
144.8 b
0.0 c
0.0 c
0.0 c 		   
0.0 c
CCSD(T)//B3LYP/6-31G(2df,p)    
0.0 c 		   
0.0 c
CCSD// MP2FC/6-31G*
0.0 c
0.0 c
0.0 c
145.7 b
0.0 c 		 
0.0 c
CCSD(T)// MP2FC/6-31G*
0.0 c
0.0 c
0.0 c
148.5 b
0.0 c 		 
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.