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

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

Isomers of C7H16

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a C7H16 591764 2-methylhexane 0.0 sketch of 2-methylhexane
b C7H16 589344 3-methylhexane 2.7 sketch of 3-methylhexane
c C7H16 142825 heptane 7.2 sketch of heptane
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
semi-empirical AM1 0.0 a
554.7 b
-10.5 c
PM3 0.0 a
PM6 0.0 a
6.3 b
2.9 c
composite G1 0.0 a
614.1 b
7.5 c
G2MP2 0.0 a
614.2 b
7.4 c
G2 0.0 a
614.5 b
7.4 c
G3 0.0 a
614.2 b
6.9 c
G3B3
NC
NC
G3MP2 0.0 a
615.2 b
7.0 c
CBS-Q 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 aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z
hartree fock HF 0.0 a
-3.1 c 		0.0 a
2.1 c 		0.0 a
2.1 c 		0.0 a
-1.7 c 		0.0 a
-2.9 c 		0.0 a
-2.7 c 		0.0 a 0.0 a
-2.7 c 		0.0 a
-2.5 c 		0.0 a
-3.0 c 		0.0 a
-2.7 c 		0.0 a
-2.9 c 		0.0 a
-3.2 c 		0.0 a
-2.7 c 		0.0 a 0.0 a
-3.2 c
density functional LSDA 0.0 a
4.1 c 		0.0 a
11.5 c 		0.0 a
11.5 c 		0.0 a
7.8 c 		0.0 a
7.3 c 		0.0 a
7.5 c 		0.0 a
7.4 c 		0.0 a
7.9 c 		0.0 a
8.5 c 		0.0 a
8.1 c 		  0.0 a
7.5 c 		0.0 a
7.7 c 		0.0 a
8.8 c 		  0.0 a
7.7 c
BLYP 0.0 a 0.0 a
1.8 c 		0.0 a
1.8 c 		0.0 a
-0.5 c 		0.0 a
-1.0 c 		0.0 a
-0.9 c 		0.0 a
-1.1 c 		0.0 a
-1.5 c 		0.0 a
-1.0 c 		0.0 a
-0.4 c 		  0.0 a
-0.9 c
NC		    
NC
B1B95 0.0 a
8.1 c 		0.0 a
6.2 c 		0.0 a
6.2 c 		0.0 a
-0.9 c 		0.0 a
1.0 c 		0.0 a
2.3 c 		0.0 a
1.7 c 		0.0 a
1.0 c 		0.0 a
1.2 c
NC		   0.0 a
2.8 c 		0.0 a
1.0 c
NC		   0.0 a
1.0 c
B3LYP 0.0 a
-1.1 c 		0.0 a
2.9 c 		0.0 a
2.9 c 		0.0 a
-0.0 c 		0.0 a
-0.6 c 		0.0 a
-0.5 c 		0.0 a
-0.5 c 		0.0 a
-0.8 c 		0.0 a
-0.3 c 		0.0 a
-0.2 c 		  0.0 a
-0.6 c 		0.0 a
-0.8 c 		0.0 a
0.1 c 		  0.0 a
-0.8 c
B3LYPultrafine         0.0 a                      
B3PW91   0.0 a
3.6 c 		0.0 a
3.6 c 		0.0 a
0.0 c 		0.0 a
-0.6 c 		0.0 a
-0.4 c 		0.0 a
-0.3 c 		0.0 a
-0.3 c 		0.0 a
0.1 c 		0.0 a
-0.3 c 		  0.0 a
-0.6 c 		0.0 a
-0.7 c 		    0.0 a
-0.7 c
mPW1PW91 0.0 a
-1.2 c 		0.0 a
11.4 c 		0.0 a
11.3 c 		0.0 a
7.3 c 		0.0 a
6.7 c 		0.0 a
6.9 c 		0.0 a
6.9 c 		0.0 a
6.9 c 		0.0 a
0.9 c 		0.0 a
0.3 c 		  0.0 a
6.9 c 		0.0 a
6.5 c 		    0.0 a
6.5 c
PBEPBE 0.0 a 0.0 a
5.0 c 		0.0 a
5.0 c 		0.0 a
1.6 c 		0.0 a
1.1 c 		0.0 a
1.3 c 		0.0 a
1.3 c 		0.0 a
1.1 c 		0.0 a
1.6 c 		0.0 a
1.5 c 		  0.0 a
1.2 c 		0.0 a
1.1 c 		    0.0 a
1.1 c
PBEPBEultrafine        
NC		                      
Moller Plesset perturbation MP2FC 0.0 a 0.0 a
8.1 c 		0.0 a
8.1 c 		0.0 a
5.3 c 		0.0 a 0.0 a
5.9 c 		0.0 a
6.9 c 		0.0 a
7.4 c 		0.0 a
7.6 c 		0.0 a
7.7 c 		  0.0 a
6.6 c
NC		 0.0 a
9.0 c 		 
NC
MP2FU 0.0 a 0.0 a
8.2 c 		0.0 a
8.2 c 		0.0 a
5.5 c 		0.0 a
6.1 c 		0.0 a
6.2 c 		0.0 a
7.2 c 		0.0 a
7.7 c 		0.0 a
7.9 c 		0.0 a
10.3 c 		  0.0 a
6.8 c 		       
MP4  
NC		                            
Configuration interaction CID   0.0 a 0.0 a 0.0 a 0.0 a     0.0 a                
CISD   0.0 a 0.0 a 0.0 a 0.0 a     0.0 a                
Quadratic configuration interaction QCISD 0.0 a 0.0 a
6.6 c 		0.0 a
6.6 c 		0.0 a
3.7 c 		0.0 a
3.4 c 		0.0 a
3.3 c 		 
NC		      
NC		        
Coupled Cluster CCD 0.0 a 0.0 a
6.4 c
NC
NC		 0.0 a
3.1 c
NC		  
NC		                
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 0.0 a
-0.5 c 		0.0 a
-0.7 c 		0.0 a
-1.8 c 		0.0 a
-2.2 c 		0.0 a
-1.7 c 		0.0 a
-1.6 c
density functional B1B95 0.0 a
3.1 c 		0.0 a
3.2 c 		       
B3LYP 0.0 a
1.6 c 		0.0 a
1.9 c 		0.0 a
0.2 c 		0.0 a
0.2 c 		0.0 a
0.8 c 		0.0 a
0.7 c
Moller Plesset perturbation MP2FC 0.0 a
8.2 c 		0.0 a
8.5 c 		0.0 a
8.9 c 		0.0 a
9.5 c 		0.0 a
8.6 c 		0.0 a
8.7 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.