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

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

Isomers of CHN

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a HCN 74908 Hydrogen cyanide 0.0 sketch of Hydrogen cyanide
b HNC 6914074 hydrogen isocyanide 62.3 sketch of hydrogen isocyanide
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
semi-empirical AM1 0.0 a
PM3 0.0 a
PM6 0.0 a
55.7 b
MNDOd 0.0 a
composite G1 0.0 a
60.0 b
G2MP2 0.0 a
56.1 b
G2 0.0 a
58.0 b
G3 0.0 a
G3B3 0.0 a
60.3 b
G3MP2 0.0 a
57.4 b
CBS-Q 0.0 a
molecular mechanics MM3 0.0 a
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 aug-cc-pVQZ cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ
hartree fock HF 0.0 a
79.5 b 		0.0 a
36.0 b 		0.0 a
36.0 b 		0.0 a
34.5 b 		0.0 a
50.5 b 		0.0 a
44.5 b 		0.0 a
38.6 b 		0.0 a
48.1 b 		0.0 a
44.1 b 		0.0 a
42.0 b 		0.0 a
41.5 b 		0.0 a
45.1 b 		0.0 a
42.2 b 		0.0 a
41.9 b 		0.0 a
41.7 b 		0.0 a
41.7 b 		0.0 a
41.6 b 		0.0 a
42.2 b 		   
density functional LSDA 0.0 a
110.1 b 		0.0 a
65.9 b 		0.0 a
65.9 b 		0.0 a
66.1 b 		0.0 a
70.0 b 		0.0 a
65.0 b 		0.0 a
56.9 b 		0.0 a
65.4 b 		0.0 a
61.8 b 		0.0 a
58.1 b 		  0.0 a
63.7 b 		0.0 a
59.4 b 		  0.0 a
57.7 b 		    0.0 a
59.4 b 		   
BLYP 0.0 a
104.6 b 		0.0 a
69.5 b 		0.0 a
69.5 b 		0.0 a
67.4 b 		0.0 a
72.7 b 		0.0 a
67.7 b 		0.0 a
59.2 b 		0.0 a
68.5 b 		0.0 a 0.0 a
61.0 b 		  0.0 a
65.4 b 		0.0 a
62.9 b 		  0.0 a     0.0 a
62.9 b 		   
B1B95 0.0 a
101.1 b 		0.0 a
60.3 b 		0.0 a
60.3 b 		0.0 a
60.7 b 		0.0 a
66.4 b 		0.0 a
61.8 b 		0.0 a
54.9 b 		0.0 a
63.1 b 		0.0 a
59.3 b 		0.0 a
56.1 b 		  0.0 a
60.6 b 		0.0 a
56.6 b 		  0.0 a     0.0 a
56.6 b 		   
B3LYP 0.0 a
100.2 b 		0.0 a
63.3 b 		0.0 a
63.3 b 		0.0 a
61.4 b 		0.0 a
68.3 b 		0.0 a
63.1 b 		0.0 a
55.3 b 		0.0 a
64.4 b 		0.0 a 0.0 a
56.9 b 		0.0 a
57.4 b 		0.0 a
61.4 b 		0.0 a
58.6 b 		0.0 a
58.0 b 		0.0 a
55.5 b 		0.0 a
57.4 b 		0.0 a
57.2 b 		0.0 a
58.6 b 		   
B3LYPultrafine         0.0 a                              
B3PW91 0.0 a
103.5 b 		0.0 a
60.8 b 		0.0 a
60.8 b 		0.0 a
61.0 b 		0.0 a
67.4 b 		0.0 a
62.0 b 		0.0 a
55.8 b 		0.0 a
64.0 b 		0.0 a 0.0 a
57.2 b 		  0.0 a
61.3 b 		0.0 a
58.3 b 		  0.0 a     0.0 a
58.3 b 		   
mPW1PW91 0.0 a
102.3 b 		0.0 a
59.4 b 		0.0 a
59.5 b 		0.0 a
61.9 b 		0.0 a
66.5 b 		0.0 a
61.0 b 		0.0 a
54.6 b 		0.0 a
63.1 b 		0.0 a 0.0 a
56.6 b 		  0.0 a
60.4 b 		0.0 a
57.3 b 		  0.0 a     0.0 a
57.3 b 		   
PBEPBE 0.0 a
109.8 b 		0.0 a
68.2 b 		0.0 a
68.2 b 		0.0 a
68.4 b 		0.0 a
72.8 b 		0.0 a
67.6 b 		0.0 a
60.1 b 		0.0 a
68.6 b 		0.0 a 0.0 a
62.3 b 		0.0 a
61.7 b 		0.0 a
66.2 b 		0.0 a
62.8 b 		  0.0 a
60.9 b 		0.0 a
61.4 b 		  0.0 a
62.8 b 		   
PBEPBEultrafine         0.0 a                              
Moller Plesset perturbation MP2FC 0.0 a
160.6 b 		0.0 a
92.2 b 		0.0 a
92.2 b 		0.0 a
96.6 b 		0.0 a
87.8 b 		0.0 a
83.9 b 		0.0 a
76.5 b 		0.0 a
83.5 b 		0.0 a
78.9 b 		0.0 a
77.1 b 		  0.0 a
80.0 b 		0.0 a
75.3 b 		  0.0 a
74.9 b 		0.0 a
74.7 b 		  0.0 a
75.3 b 		0.0 a 0.0 a
MP2FU   0.0 a
92.0 b
NC
NC		 0.0 a
88.1 b 		0.0 a
84.1 b 		0.0 a
76.6 b 		0.0 a
83.6 b 		0.0 a
79.0 b 		    0.0 a
80.1 b 		0.0 a
76.8 b 		  0.0 a
75.0 b 		0.0 a   0.0 a
76.8 b 		0.0 a 0.0 a
MP3         0.0 a
69.6 b 		                             
MP4   0.0 a
69.9 b 		    0.0 a 0.0 a 0.0 a 0.0 a       0.0 a 0.0 a         0.0 a    
Configuration interaction CID    
NC
NC		 0.0 a
67.9 b 		    0.0 a
63.5 b 		                       
CISD   0.0 a
NC
NC		 0.0 a
67.8 b 		0.0 a  
NC		                        
Quadratic configuration interaction QCISD   0.0 a
73.7 b
NC
NC		 0.0 a
71.4 b 		0.0 a
67.9 b 		0.0 a
60.7 b 		0.0 a
66.5 b 		0.0 a
62.5 b 		    0.0 a
63.5 b 		               
QCISD(T)   0.0 a     0.0 a 0.0 a 0.0 a 0.0 a       0.0 a 0.0 a         0.0 a    
Coupled Cluster CCD  
NC
NC
NC		 0.0 a
72.6 b
NC		   0.0 a
67.4 b 		      0.0 a
64.6 b 		               
CCSD   0.0 a     0.0 a
72.5 b 		0.0 a 0.0 a 0.0 a       0.0 a                
CCSD(T)         0.0 a
74.2 b 		0.0 a   0.0 a       0.0 a 0.0 a
62.2 b 		  0.0 a 0.0 a   0.0 a
62.2 b 		0.0 a 0.0 a
CCSD(T)=FULL         0.0 a             0.0 a 0.0 a   0.0 a 0.0 a   0.0 a 0.0 a 0.0 a
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 0.0 a
18.2 b 		0.0 a
36.6 b 		0.0 a
23.5 b 		0.0 a
44.9 b 		0.0 a
22.9 b 		0.0 a
22.9 b
density functional B1B95 0.0 a
43.5 b 		0.0 a
52.3 b 		       
B3LYP 0.0 a
37.0 b 		0.0 a
48.8 b 		0.0 a
43.1 b 		0.0 a
56.8 b 		0.0 a
48.5 b 		0.0 a
48.8 b
Moller Plesset perturbation MP2FC 0.0 a
74.3 b 		0.0 a
72.1 b 		0.0 a
82.2 b 		0.0 a
79.8 b 		0.0 a
84.5 b 		0.0 a
84.7 b
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 a
69.4 b 		0.0 a 0.0 a
69.8 b 		0.0 a 0.0 a 0.0 a
69.8 b
MP2FC// B3LYP/6-31G* 0.0 a
72.7 b 		0.0 a
76.6 b 		0.0 a
73.3 b 		0.0 a 0.0 a 0.0 a
73.3 b
MP2FC// MP2FC/6-31G* 0.0 a
74.4 b 		0.0 a 0.0 a
75.3 b 		0.0 a
75.1 b 		  0.0 a
75.3 b
MP4// HF/6-31G* 0.0 a
61.4 b 		  0.0 a
61.5 b 		    0.0 a
61.5 b
MP4// B3LYP/6-31G*   0.0 a
65.1 b 		0.0 a
64.1 b 		    0.0 a
64.1 b
MP4// MP2/6-31G* 0.0 a
59.6 b 		  0.0 a
65.7 b 		    0.0 a
65.7 b
Coupled Cluster CCSD// HF/6-31G* 0.0 a 0.0 a
NC		 0.0 a 0.0 a
NC
CCSD(T)// HF/6-31G* 0.0 a 0.0 a 0.0 a
59.0 b 		0.0 a 0.0 a 0.0 a
59.0 b
CCSD// B3LYP/6-31G* 0.0 a
59.5 b 		0.0 a 0.0 a 0.0 a   0.0 a
CCSD(T)// B3LYP/6-31G* 0.0 a
60.8 b 		0.0 a 0.0 a 0.0 a   0.0 a
CCSD(T)//B3LYP/6-31G(2df,p)     0.0 a
61.3 b 		    0.0 a
61.3 b
CCSD// MP2FC/6-31G* 0.0 a
59.0 b 		0.0 a 0.0 a 0.0 a
59.7 b 		  0.0 a
CCSD(T)// MP2FC/6-31G* 0.0 a
61.1 b 		0.0 a 0.0 a 0.0 a
61.1 b 		  0.0 a
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.