National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 17bSeptember 2015
NIST Standard Reference Database 101
IIntroduction
IIExperimental data
IIICalculated data
IVData comparisons
VCost comparisons
VIInput and output files
VIITutorials and Units
VIIILinks to other sites
IXFeedback
XOlder CCCBDB versions
XIIGeometries
XIII Vibrations
XIVReaction data
XVEntropy data
XVIBibliographic data
XVIIIon data
XVIIIBad calculations
XIXIndex of properties
XXH-bond dimers
XXIOddities

NIST policy on privacy, security, and accessibility.

Please rate our products
© 2013 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved.

The National Institute of Standards and Technology (NIST) is an agency of the U.S. Department of Commerce.

Please send questions, comments, corrections, additions and suggestions to cccbdb@nist.gov.

return to home page

XVII.C.1. (III.D.6.)

Calculated Ionization Energy for HO2 (Hydroperoxy radical)

Experimental Ionization Energy is 11.35 ± 0.01 eV
Please note! These calculated ionizataion energies have the vibrational zero-point energy (zpe) included, but the zpe has NOT been scaled. Click on an entry for more details, including the ionization energy with a scaled zpe.
Original data displayed. Press to display differences.
Differences displayed. Press to display original data.

Ionization Energies in eV
Methods with predefined basis sets
composite G2 11.342
G3 11.326
G3B3 11.319
CBS-Q 11.326

Ionization Energies in eV
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) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ
hartree fock HF 8.237     10.979 10.346 10.320 10.399 10.344 10.328 10.191 10.346 10.273 10.227 10.227 10.324 10.261 10.239
ROHF       10.883 10.189 10.163 10.421 10.186 10.170     10.118 10.041 10.033 10.147 10.067 10.043
density functional LSDA 8.635 11.428 11.428 11.831 11.532 11.511 11.796 11.668 11.664 11.431   11.427 11.663   11.759 11.757  
BLYP 8.177 10.794 10.794 11.271 11.053 10.925 11.265 11.079 11.073 10.828   10.836 11.097        
B1B95 8.545 11.170 11.170 11.441 11.040 11.172 11.219 11.268 11.095 10.920   11.050 11.064   11.171 11.139  
B3LYP 8.601 11.230 11.230 11.593 11.213 11.192 11.453 11.314 11.306 11.091 11.405 11.114 11.296 11.338 11.403 11.390 11.376
B3LYPultrafine         11.214                        
B3PW91 8.608 11.293 11.293 11.573 11.177 11.153 11.354 11.254 11.245 11.053   11.093 11.204        
mPW1PW91 8.625 11.311 11.311 11.562 11.149 11.123 11.323 11.215 11.204 11.022   11.066 11.162   11.277 11.235  
M06-2X     -11.453                            
PBEPBE 8.211 10.912 10.912 11.306 10.956 10.934 11.223 11.061 11.054 10.845   10.867 11.064   11.189 11.178  
TPSSh         11.079   11.263           11.117        
wB97X-D     9.799   9.675       9.773       9.743     9.828  
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ
Moller Plesset perturbation MP2 7.596 10.692 10.692 11.063 10.827 10.851 11.065 11.089 10.860 10.908   10.719 11.089 11.227 11.090 11.230  
MP2=FULL 7.596 10.692 10.693 11.064 10.700 10.852 11.066 10.814 10.863 10.908   10.721 11.084 11.234 11.092 11.220 11.291
ROMP2   10.723 10.723 11.079 10.728 10.754 10.969 10.701 10.751 10.790   10.610 10.974   10.980    
MP3         10.912                        
MP3=FULL         10.912   11.110                    
MP4   10.682     10.806       10.836       11.078        
B2PLYP                         11.146        
Configuration interaction CID   10.928 10.928 11.204 10.831     10.814                  
CISD   10.785 10.785 11.136 10.793     10.775                  
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ
Quadratic configuration interaction QCISD   10.523 10.523 11.071 10.869 10.886 11.094 10.856 10.895 10.952   10.769 11.107   11.126 11.240  
QCISD(T)         10.844             10.743 11.111        
Coupled Cluster CCD   10.926 10.926 11.242 10.915 10.933 11.116 10.903 10.940 10.996   10.813 11.146   11.132 11.265  
CCSD         10.890             10.786 11.121        
CCSD(T)         10.857             10.753 11.121 11.260 11.144 11.275 11.320
CCSD(T)=FULL         68.429             10.755 11.114   11.145 11.263  
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ

Ionization Energies in eV
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 10.937 10.389 10.877 10.358 10.891 10.888
density functional B3LYP 11.677 11.333 11.655 11.346 11.629 11.618
Moller Plesset perturbation MP2 11.148 10.932 11.168 10.965 11.130 11.131
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.