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IV.D.1. (XII.C.1.)

Geometry Comparison

Ne2 (Neon dimer)


distance is atom 1 (Ne) to atom 2 (Ne)

Experimental bond length is 3.100  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM6 2.715
composite G2 2.992
G3 2.992
G3B3 2.988
G4 2.639
CBS-Q 2.996

Calculated bond length in Å
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 3.000 3.000 3.000 2.928 2.686 2.686 3.260 2.894 2.894 2.635 3.469 2.811 3.122 3.448 3.644 3.645 3.817
density functional LSDA 2.927 3.070 3.070 2.359 2.341 2.341 2.841 2.438 2.438 2.312   2.369 2.539   2.841 2.598  
BLYP 3.000 3.120 3.120 2.836 2.477 2.477 3.207 2.669 2.669 2.434   2.789 2.822        
B1B95 3.109 3.316 3.316 2.997 2.994 2.994 4.055 2.922 2.922 2.584   2.997 2.942   4.340 2.977  
B3LYP 3.000 3.107 3.107 2.841 2.478 2.478 3.139 2.650 2.650 2.446 3.096 2.841 2.802 3.074 3.536 3.118 3.508
B3LYPultrafine         2.506                     2.708  
B3PW91 3.057 3.421 3.421 3.159 2.841 2.841 4.030 3.138 3.138 2.563   3.159 3.154        
mPW1PW91 3.000 3.334 3.334 2.841 2.578 2.578 3.225 2.764 2.764 2.528   2.841 2.948   3.478 3.292  
M06-2X 3.018 2.910 2.910 2.636 2.569 2.569 2.977 2.693 2.693 2.505   2.649 2.877   2.979 3.017  
PBEPBE 2.954 3.252 3.252 2.532 2.492 2.492 3.051 2.638 2.638 2.449   2.556 2.796   3.102 3.000  
HSEh1PBE 3.000 3.054 3.054 2.841 2.520 2.520 3.159 2.662 2.662 2.484   2.841 2.845   3.130 3.000  
TPSSh         2.988   3.005           2.993        
Moller Plesset perturbation MP2   2.841 2.841 2.841 2.593 2.593 3.160 2.820 2.820 2.531 3.310 2.741 2.982 3.185 3.289 3.164 3.192
MP2=FULL   2.841 2.841 2.841 2.589 2.589 3.134 2.818 2.818 2.527   2.741 2.977 3.178 3.274 3.109 3.174
MP3         2.603   2.987                    
MP3=FULL         2.986   3.004                    
MP4   2.507     2.591       2.820       2.976        
Configuration interaction CID   2.987 2.987 2.908 2.610     2.841                  
CISD   2.987 2.987   2.605     2.837                  
Quadratic configuration interaction QCISD         2.599 2.599 3.138 2.831 2.831 2.534   2.752 3.000   3.254 3.135  
QCISD(T)         2.594             2.746 2.983        
Coupled Cluster CCD   3.000 3.000 3.096 2.605 2.605 3.141 2.837 2.837 2.542   2.756 3.000   3.272 3.146  
CCSD         2.601             2.754 3.000        
CCSD(T)         2.595             2.746 2.983 3.167 3.215 3.091 3.093
CCSD(T)=FULL         2.592             2.746 2.976 3.160 3.203 3.048 3.075

Calculated bond length in Å
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 3.309   3.273   3.097 3.096
density functional B3LYP 2.940   2.884   2.756 2.755
Moller Plesset perturbation MP2 3.221   3.174   3.033 3.031
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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