return to home page

XVII.C.1.

Calculated Ionization Energy for N2 (Nitrogen diatomic)

Experimental Ionization Energy is 15.581 ± 0.008 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
semi-empirical PM3  
PM6  
composite CBS-Q 15.549
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 cc-pV(T+d)Z
hartree fock HF 13.961 15.545 15.545 15.721 15.714 15.714 15.736 15.737 15.737 15.658 15.742 15.635 15.688   15.716 15.705   15.688
density functional LSDA 14.616 15.698 15.698 15.916 16.007 16.007 16.122 16.100 16.100 15.968   15.899 16.093   16.097     16.093
BLYP 13.863 14.855 14.855 15.095 15.183 15.183 15.333 15.259 15.259 15.151   15.069 15.281         15.281
B3LYP 14.336 15.428 15.428 15.641 15.714 15.714 15.823 15.779 15.779 15.677 15.832 15.610 15.784   15.802 15.831   15.784
B3LYPultrafine         15.714                          
B3PW91 14.395 15.505 15.505 15.642 15.700 15.700 15.770 15.746 15.746 15.655   15.611 15.728         15.728
mPW1PW91 14.415 15.519 15.543 15.674 15.702 15.702 15.776 15.746 15.767 15.680   15.616 15.730         15.730
M06-2X         16.033                          
PBEPBE 14.003 14.998 14.998 15.178 15.246 15.246 15.366 15.303 15.303 15.216   15.150 15.314         15.314
Moller Plesset perturbation MP2FC 12.606 14.222 14.222 14.505 14.964 14.964 15.058 15.010 15.010 15.146 15.039 14.867 15.224 15.336 15.121   15.375 15.224
MP2FU   14.222     14.970 14.970 15.065 15.021 15.021     14.872 15.247 15.364 15.126     15.247
MP3         15.619                          
MP4         14.878                          
B2PLYP             15.439                      
Configuration interaction CID         15.483     15.531                    
CISD         15.389                          
Quadratic configuration interaction QCISD   14.445     15.217 15.217 15.294 15.266 15.266       15.498         15.498
QCISD(T)         15.099                          
Coupled Cluster CCD         15.385     15.435                    
CCSD         15.270                          
CCSD(T)   14.382     15.124   15.208   15.164       15.404         15.404
CCSD(T)=FULL         15.129                          
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 15.564 15.554 15.516 15.626 15.523 15.520
density functional B3LYP 15.523 15.585 15.520 15.656 15.519 15.499
Moller Plesset perturbation MP2FC 14.357 14.848 14.445 14.939 14.331 14.336
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.