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

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

Isomers of CH4O3

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a HCOOHH2O 99 Formic acid water dimer   sketch of Formic acid water dimer
b H2OHCOOH 102 Water formic acid dimer 1   sketch of Water formic acid dimer 1
c H2OHCOOH 113 Water formic acid dimer 2   sketch of Water formic acid dimer 2
d HOCH2OOH 15932895 hydroxy methyl peroxide   sketch of hydroxy methyl peroxide
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
semi-empirical PM3 -470.6 a
-485.1 b
-486.2 c
PM6 -631.5 a
-611.6 b
-613.6 c
composite G1
NC
NC
G2MP2
NC
NC
G2
NC
NC
G3B3 NC
G3MP2 NC
NC
NC
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) 6-311+G(3df,2pd) cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z
hartree fock HF   NC
NC
NC		     NC
NC
NC		  
NC
NC		       NC
NC
NC		 NC
NC
NC		       NC
NC
NC		  
density functional LSDA NC
NC		 NC
NC
NC		 NC
NC
NC		 NC
NC
NC		 NC
NC
NC		 NC
NC
NC		 NC
NC
NC		 NC
NC
NC		 NC
NC
NC		 NC
NC
NC		     NC
NC
NC		 NC
NC
NC		 NC
NC
NC		   NC
NC
NC
B1B95 NC
NC
NC		 NC
NC		 NC NC
NC
NC		 NC
NC
NC		 NC
NC
NC		 NC
NC
NC		 NC
NC		 NC
NC		 NC
NC
NC		     NC
NC
NC		 NC
NC
NC		 NC
NC
NC		   NC
NC
NC
B3LYP   NC
NC
NC		     NC
NC
NC		   NC
NC
NC		         NC
NC
NC		       NC
NC
NC		  
B3LYPultrafine   NC
NC
NC		     NC
NC
NC		   NC
NC
NC		         NC
NC
NC		       NC
NC
NC		  
PBEPBE   NC
NC
NC		     NC
NC
NC		   NC
NC
NC		         NC
NC
NC		       NC
NC
NC		  
PBEPBEultrafine   NC
NC
NC		     NC
NC
NC		   NC
NC
NC		         NC
NC
NC		       NC
NC
NC		  
Moller Plesset perturbation MP2FC   NC
NC
NC		     NC
NC
NC		   NC
NC
NC		         NC
NC
NC		          
Coupled Cluster CCSD(T)   NC
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      
NC
NC		  
density functional B1B95 NC
NC
NC		 NC
NC		        
B3LYP      
NC
NC		  
Moller Plesset perturbation MP2FC      
NC
NC		  
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* NC
NC
NC		   NC
NC
NC		   NC
NC
NC
MP2FC// B3LYP/6-31G* NC NC
NC
NC		 NC
NC
NC		   NC
NC
NC
MP2FC// MP2FC/6-31G*     NC
NC
NC		 NC
NC
NC		 NC
NC
NC
MP4// HF/6-31G* NC
NC
NC		   NC
NC
NC		   NC
NC
NC
MP4// B3LYP/6-31G*   NC
NC
NC		 NC
NC
NC		   NC
NC
NC
MP4// MP2/6-31G*     NC
NC
NC		   NC
NC
NC
Coupled Cluster CCSD// B3LYP/6-31G* NC        
CCSD(T)// B3LYP/6-31G* NC        
CCSD// MP2FC/6-31G*       NC
NC
NC		  
CCSD(T)// MP2FC/6-31G*       NC
NC
NC		  
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.