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Calculated Ionization Energy for Na2 (Sodium diatomic)

Experimental Ionization Energy is 4.892 ± 0.003 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 PM6  
composite G4 4.880
CBS-Q 4.864

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 -4.411 3.955 3.905 3.988 3.964 3.964 3.966 3.981 3.981 3.960 4.008 3.950 3.958 3.958 3.954 3.959 3.958 3.958
density functional LSDA -1.216 5.411 5.901 5.610 5.602 5.602 5.603 5.607 5.607 5.616 5.605 5.582 5.583 5.596 5.588 5.584 5.598 5.583
SVWN   5.508     5.602 5.602 5.603 5.607 5.607 5.616 5.605 5.582 5.583   5.588 5.584    
BLYP -1.840 5.099 5.379 5.093 5.083 5.083 5.084 5.086 5.086 5.086 5.091 5.070 5.068   5.076 5.070    
B1B95 -2.462 4.624 4.865 4.870 4.827 4.858         4.833 4.838 4.778     4.803   4.778
B3LYP -2.000 5.141 5.377 5.150 5.138 5.138 5.138 5.135 5.135 5.134 5.150 5.123 5.116 5.124 5.127 5.117 5.126 5.116
B3LYPultrafine   5.141     5.138 5.138 5.138 5.135     5.150 5.123 5.116   5.127 5.117    
B3PW91 -2.301 4.859 4.973 4.901 4.885 4.885 4.885 4.884 4.884 4.875 4.902 4.865 4.859   4.867 4.860    
mPW1PW91 -2.413 4.876 4.896 4.904 4.861 4.861 4.862 4.860 4.885 4.874 4.906 4.865 4.859   4.867 4.859   4.859
M06-2X -2.409 5.124 5.255 5.260 5.254 5.254 5.255 5.256 5.256 5.260 5.264 5.239 5.233   5.243 5.235    
PBEPBE -1.975 5.063 5.279 5.076 5.062 5.062 5.062 5.063 5.063 5.051 5.073 5.043 5.040 5.045 5.048 5.040 5.047 5.040
PBEPBEultrafine   5.063     5.062 5.062 5.062 5.063     5.073 5.043 5.040   5.048 5.040    
PBE1PBE -2.385 4.842 5.080 4.956 4.939 4.939 4.939 4.938 4.938 4.927 4.958 4.920 4.914   4.922 4.914    
HSEh1PBE -2.341 4.946 5.095 4.965 4.948 4.948 4.948 4.946 4.946 4.935 4.966 4.930 4.924   4.932 4.924    
TPSSh         4.906   4.906     4.891     4.878          
wB97X-D     4.629   4.736   4.736   4.756   4.743 4.100 4.715     4.715    
B97D3   5.122     5.124       5.157             5.116    
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
Moller Plesset perturbation MP2 -3.987 4.338 4.399 4.382 4.442 4.423 4.424 4.396 4.398 4.470 4.462 4.420 4.409 4.494 4.481 4.482 3.363 4.489
MP2=FULL -3.672 4.346 4.401 4.391 4.458 4.458 4.460 4.505 4.505 4.609 4.406 4.435 4.569 4.714 4.452 4.585    
MP3         4.559   4.561       4.511 4.564 4.596          
MP3=FULL         4.595   4.597                      
MP4   4.544     4.616       4.627   4.572 4.623 4.651   4.627 4.651    
MP4=FULL   4.551     4.653       4.700     4.637 4.749   4.650 4.761    
B2PLYP -2.828   5.000   4.857 4.857   4.771 4.771 4.881 4.929 4.570 4.980   4.906 4.801    
B2PLYP=FULL -2.634 4.869 5.063 4.879 4.895 4.895 4.895 4.907 4.907 4.939 4.882 4.875 4.914   4.882 4.920    
Configuration interaction CID   4.581 4.614 4.619 4.655     4.668                    
CISD     4.618 4.627 4.660     4.672                    
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
Quadratic configuration interaction QCISD   4.589 4.618 4.627 4.660 4.660 4.661 4.672 4.672 4.697 4.618 4.668 4.698   4.673 4.698   4.698
QCISD(T)         4.660     4.672     4.618 4.668 4.698   4.673 4.698    
Coupled Cluster CCD   4.581 4.614 4.619 4.655 4.655 4.657 4.668 4.668 4.692 4.609 4.664 4.694   4.669 4.694    
CCSD         4.660         4.697 4.618 4.668 4.698 4.700 4.673 4.698 4.700  
CCSD=FULL         4.688         4.813 4.635 4.678 4.778 4.901 4.690 4.789    
CCSD(T)         4.660 4.660 4.661 4.672 4.672 4.697 4.618 4.668 4.698 4.700 4.673 4.698 4.700 4.698
CCSD(T)=FULL         110.688           4.649 4.681 4.792 4.920 4.694 4.804 6.557  
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

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 3.821 3.833 4.011 3.984 3.853 4.042
density functional B3LYP 4.671 4.663 4.802 4.779 4.686 5.150
Moller Plesset perturbation MP2 4.200 4.289 4.385 4.425 4.244 4.436
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.