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Comparison of experiment and theory for rSiSi

18 10 23 14 56
Species with coordinate rSiSi
Species Name
Si2H6 disilane
Si2 Silicon diatomic
Si2H2 disilyne
The small prefix is the number of bonds with completed calculations.
Click on an entry for a histogram of the difference distribution.
rms differences (calculated - experiment) in Å
Methods with predefined basis sets
semi-empirical AM1 3 0.271
PM3 2 0.053
PM6 3 0.268
composite G2 2 0.033
G3 2 0.033
G3B3 3 0.030
G3MP2 1 0.032
G4 3 0.022
CBS-Q 2 0.033

rms differences (calculated - experiment) 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) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pV(D+d)Z cc-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ aug-cc-pCVTZ daug-cc-pVDZ daug-cc-pVTZ
hartree fock HF 2 0.102 3 0.074 3 0.032 3 0.068 3 0.066 3 0.066 3 0.066 3 0.068 2 0.038 3 0.070 3 0.070 3 0.067 3 0.063 3 0.035 2 0.040 3 0.032 2 0.040 2 0.040 1 0.046 1 0.045 1 0.045 1 0.053 1 0.046 1 0.046 2 0.039 3 0.067
density functional LSDA 2 0.081 1 0.016 1 0.019 2 0.085 2 0.029 1 0.001 1 0.002 2 0.027 1 0.001 1 0.000     1 0.009 1 0.002   1 0.008     1 0.002 1 0.007 1 0.007 1 0.005 1 0.005 1 0.005    
BLYP 2 0.049 3 0.089 3 0.036 3 0.092 3 0.050 3 0.055 3 0.055 3 0.056 2 0.042 2 0.039 3 0.042 2 0.046 3 0.063 3 0.047   2 0.053 2 0.040   1 0.045 1 0.042 1 0.042 1 0.052 1 0.045 1 0.044 2 0.053 2 0.040
B1B95 2 0.083 2 0.026 2 0.017 2 0.066 2 0.012 2 0.013 2 0.014 2 0.014 2 0.014 2 0.014 2 0.013 2 0.013 2 0.016 2 0.012   2 0.015 2 0.012   1 0.013 1 0.012 1 0.012 1 0.020 1 0.013 1 0.013 1 0.008 2 0.012
B3LYP 2 0.068 3 0.070 3 0.016 3 0.100 3 0.029 3 0.047 3 0.047 3 0.050 2 0.025 3 0.052 2 0.021 3 0.049 3 0.048 3 0.026 2 0.021 3 0.036 2 0.023 2 0.021 1 0.033 1 0.030 1 0.030 1 0.040 1 0.032 1 0.031 2 0.033 2 0.024
B3LYPultrafine   2 0.084     2 0.022 2 0.022 2 0.024 2 0.024   2 0.024 3 0.021 2 0.028 2 0.034 2 0.024   2 0.033 3 0.022   1 0.033 1 0.030 1 0.030 1 0.040 1 0.032 1 0.031 2 0.033 2 0.024
B3PW91 2 0.076 3 0.064 3 0.015 3 0.089 3 0.051 3 0.051 3 0.022 3 0.023 2 0.020 3 0.056 3 0.016 2 0.022 3 0.028 3 0.054   2 0.025 2 0.019   1 0.025 1 0.022 1 0.023 1 0.032 1 0.025 1 0.024 2 0.026 2 0.019
mPW1PW91 2 0.080 3 0.061 2 0.016 2 0.070 3 0.054 3 0.018 3 0.018 3 0.056 2 0.019 2 0.020 3 0.015 2 0.020 3 0.023 3 0.056   2 0.022 2 0.018   1 0.022 1 0.020 1 0.020 1 0.029 1 0.022 1 0.021 2 0.022 2 0.018
M06-2X 2 0.087 2 0.064 3 0.066 2 0.069 3 0.056 2 0.010 2 0.012 2 0.013 2 0.014 2 0.013 3 0.060 2 0.017 2 0.023 2 0.014   2 0.022 2 0.013   1 0.019 1 0.016 1 0.016 1 0.026 1 0.018 1 0.017 2 0.022 2 0.013
PBEPBE 2 0.063 2 0.091 2 0.009 2 0.092 2 0.025 2 0.026 2 0.026 2 0.028 2 0.028 2 0.026 3 0.030 2 0.031 2 0.039 2 0.027   2 0.038 2 0.026   1 0.030 1 0.028 1 0.028 1 0.037 1 0.030 1 0.030 2 0.038 2 0.026
PBEPBEultrafine   2 0.091     2 0.025 2 0.025 2 0.026 2 0.027   2 0.025 2 0.022 2 0.031 2 0.038 2 0.027   2 0.038 2 0.026   1 0.030 1 0.028 1 0.028 1 0.037 1 0.030 1 0.029 2 0.038 2 0.026
PBE1PBE 2 0.082 2 0.016 2 0.016 2 0.070 3 0.053 2 0.015 2 0.017 2 0.017 2 0.019 2 0.019 2 0.017 2 0.019 2 0.022 2 0.017   2 0.022 2 0.018   1 0.021 1 0.020 1 0.020 1 0.029 1 0.022 1 0.021 2 0.022 2 0.017
HSEh1PBE 2 0.081 3 0.062 2 0.015 2 0.072 3 0.052 2 0.015 3 0.052 2 0.017 2 0.018 2 0.019 2 0.017 2 0.020 2 0.023 3 0.055   2 0.023 2 0.017   1 0.022 1 0.020 1 0.021 1 0.029 1 0.022 1 0.022 2 0.023 2 0.017
TPSSh 2 0.071 2 0.087 2 0.010 2 0.083 3 0.053 2 0.018 3 0.054 2 0.021 2 0.022 3 0.056 2 0.018 2 0.025 2 0.030 3 0.056 2 0.019 2 0.030 2 0.021 2 0.019 1 0.028 1 0.026 1 0.026 1 0.035 1 0.028 1 0.027 2 0.030 2 0.021
wB97X-D 2 0.086 2 0.056 3 0.068 2 0.057 3 0.062 2 0.020 3 0.062 2 0.021 3 0.064 2 0.023 2 0.022 3 0.062 3 0.061 3 0.063 2 0.022 2 0.020 3 0.062 2 0.022 1 0.021 1 0.019 1 0.019 1 0.028 1 0.020 1 0.020 2 0.020 2 0.021
B97D3 2 0.056 3 0.083 2 0.014 2 0.098 3 0.048 2 0.028 3 0.049 2 0.030 3 0.051 2 0.029 3 0.052 3 0.046 2 0.043 3 0.051 2 0.025 2 0.042 3 0.046 2 0.024 1 0.035 1 0.032 1 0.031 1 0.042 1 0.034 1 0.033 2 0.042 3 0.046
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) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pV(D+d)Z cc-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ aug-cc-pCVTZ daug-cc-pVDZ daug-cc-pVTZ
Moller Plesset perturbation MP2 2 0.070 3 0.136 3 0.014 3 0.129 3 0.015 3 0.045 3 0.045 3 0.016 2 0.017 3 0.049 3 0.050 3 0.044 3 0.043 3 0.019 3 0.014 3 0.039 2 0.021 3 0.014 1 0.034 2 0.020 1 0.026 1 0.040 1 0.027 1 0.027 2 0.040 2 0.021
MP2=FULL 2 0.071 3 0.138 3 0.016 3 0.129 3 0.014 3 0.047 3 0.047 3 0.050 2 0.015 2 0.018 3 0.052 2 0.023 3 0.042 2 0.012 3 0.012 3 0.034 3 0.011 2 0.013 1 0.024 2 0.006 1 0.007 1 0.034 1 0.016 1 0.015 2 0.036 2 0.012
MP3         1 0.020   2 0.061       1 0.025 1 0.033 2 0.043 1 0.032         1 0.037 1 0.029 1 0.028 1 0.043 1 0.029 1 0.029 1 0.046 1 0.031
MP3=FULL   1 0.078 1 0.000 1 0.071 2 0.063 1 0.014 2 0.015 1 0.018 1 0.020 1 0.023 1 0.017 1 0.033 1 0.040 1 0.019   1 0.043 1 0.019   1 0.028 1 0.011 1 0.011 1 0.038 1 0.020 1 0.020 1 0.043 1 0.016
MP4   2 0.135 1 0.012 1 0.160 2 0.024   1 0.063 2 0.051 1 0.022   2 0.052 1 0.034 1 0.045 2 0.028   2 0.050 1 0.030   1 0.036 1 0.029 1 0.028 1 0.042 1 0.029 1 0.028 1 0.048 1 0.031
MP4=FULL   1 0.081     1 0.015       1 0.021   1 0.017   1 0.039 1 0.018   1 0.044 1 0.017   1 0.029 1 0.011 1 0.010 1 0.038 1 0.020 1 0.019 1 0.044 1 0.016
B2PLYP 2 0.071 2 0.096 2 0.013 2 0.096 3 0.044 2 0.016 2 0.018 2 0.018 2 0.019 2 0.022 2 0.017 2 0.025 2 0.032 3 0.019   2 0.033 2 0.021   1 0.030 1 0.026 1 0.026 1 0.037 1 0.027 1 0.026 2 0.033 2 0.020
B2PLYP=FULL 2 0.072 2 0.096 2 0.014 2 0.096 2 0.015 2 0.015 2 0.017 2 0.017 2 0.019 2 0.019 2 0.016 2 0.024 2 0.030 2 0.018   2 0.031 2 0.018   1 0.027 1 0.020 1 0.020 1 0.035 1 0.024 1 0.023 2 0.031 2 0.018
B2PLYP=FULLultrafine 2 0.072 2 0.096 2 0.014 2 0.096 3 0.021 2 0.015 2 0.017 2 0.017 2 0.019 2 0.019 2 0.016 2 0.024 3 0.033 3 0.018   2 0.031 3 0.017   1 0.027 1 0.020 1 0.020 1 0.035 1 0.024 1 0.023 2 0.031 2 0.017
Configuration interaction CID   3 0.085 3 0.021 3 0.113 3 0.054   1 0.004 3 0.058     3 0.019   3 0.030 3 0.056         1 0.037 1 0.029 1 0.028 1 0.043 1 0.029 1 0.029 2 0.035 2 0.024
CISD   3 0.087 3 0.019 3 0.115 3 0.051 1 0.085 1 0.007 2 0.020     3 0.018   3 0.031 3 0.055         1 0.036 1 0.028 1 0.028 1 0.043 1 0.028 1 0.028 2 0.035 2 0.023
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) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pV(D+d)Z cc-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ aug-cc-pCVTZ daug-cc-pVDZ daug-cc-pVTZ
Quadratic configuration interaction QCISD   3 0.100 3 0.013 3 0.129 3 0.015 2 0.014 3 0.044 3 0.047 2 0.016 2 0.025 3 0.050 2 0.026 3 0.042 3 0.019   3 0.040 2 0.022   1 0.037 1 0.029 1 0.028 1 0.044 1 0.029 1 0.029 2 0.042 2 0.022
QCISD(T)         3 0.039   1 0.025 3 0.019     3 0.017 2 0.029 3 0.046 3 0.042   3 0.044 2 0.024   1 0.037 1 0.029 1 0.029 1 0.043 1 0.029 1 0.028 2 0.049 2 0.024
QCISD(T)=FULL         2 0.011   2 0.012       2 0.012   2 0.038 2 0.013 2 0.013 2 0.044 2 0.013 2 0.012 1 0.029 1 0.011 1 0.010 1 0.039 1 0.020 1 0.019 2 0.045 2 0.012
QCISD(TQ)         1 0.020           1 0.025         1 0.049                    
QCISD(TQ)=FULL         1 0.015               1 0.040                          
Coupled Cluster CCD   2 0.117 3 0.017 3 0.125 3 0.016 2 0.016 3 0.049 3 0.053 2 0.017 2 0.027 3 0.054 2 0.026 3 0.044 3 0.020   3 0.038 2 0.023   1 0.038 1 0.030 1 0.030 1 0.045 1 0.030 1 0.030 2 0.041 2 0.023
CCSD         3 0.045 2 0.014 3 0.015 3 0.015 2 0.017 2 0.026 3 0.015 2 0.026 3 0.037 3 0.049 2 0.020 3 0.043 2 0.022 1 0.014 1 0.037 1 0.029 1 0.028 1 0.044 1 0.029 1 0.029 2 0.041 2 0.022
CCSD=FULL         2 0.014         2 0.022 2 0.016 2 0.025 2 0.033 2 0.017 1 0.023 2 0.037 2 0.018 1 0.025 1 0.028 1 0.011 1 0.012 1 0.039 1 0.020 1 0.020 2 0.038 2 0.017
CCSD(T)         3 0.040 3 0.040 2 0.015 3 0.018 2 0.017 2 0.026 2 0.018 2 0.029 3 0.045 3 0.043 2 0.016 3 0.044 2 0.023 1 0.001 1 0.037 1 0.029 1 0.030 1 0.043 1 0.029 1 0.028 2 0.049 2 0.023
CCSD(T)=FULL         2 0.011           2 0.012 2 0.029 2 0.038 2 0.013 2 0.013 2 0.044 2 0.013 1 0.012 1 0.029 1 0.011 1 0.010 1 0.039 1 0.020 1 0.020 2 0.044 2 0.012
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) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pV(D+d)Z cc-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ aug-cc-pCVTZ daug-cc-pVDZ daug-cc-pVTZ

rms differences (calculated - experiment) in Å
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD cc-pVTZ-PP aug-cc-pVTZ-PP Def2TZVPP
hartree fock HF 3 0.083 3 0.032 3 0.079 3 0.034 3 0.035 3 0.078     3 0.070
density functional BLYP                 2 0.034
B1B95 1 0.062 2 0.048             2 0.013
B3LYP 3 0.125 3 0.047 3 0.122 3 0.043 3 0.078 3 0.110     3 0.018
B3LYPultrafine                 2 0.021
B3PW91                 2 0.017
mPW1PW91                 2 0.017
M06-2X                 2 0.011
PBEPBE                 3 0.052
PBEPBEultrafine                 2 0.022
PBE1PBE                 2 0.017
HSEh1PBE                 2 0.017
TPSSh                 2 0.018
wB97X-D 2 0.087 2 0.031 2 0.083 2 0.029 2 0.038 2 0.062     2 0.022
B97D3                 2 0.024
Moller Plesset perturbation MP2 3 0.148 3 0.035 3 0.141 3 0.029 3 0.092 3 0.139     3 0.053
MP2=FULL                 2 0.012
MP3                 1 0.027
MP3=FULL                 1 0.019
MP4                 1 0.026
MP4=FULL                 1 0.019
B2PLYP                 2 0.018
B2PLYP=FULL                 2 0.016
B2PLYP=FULLultrafine                 2 0.016
Configuration interaction CID                 2 0.024
CISD                 2 0.023
Quadratic configuration interaction QCISD                 2 0.020
QCISD(T)                 2 0.019
QCISD(T)=FULL                 2 0.014
Coupled Cluster CCD                 2 0.021
CCSD                 2 0.020
CCSD=FULL                 2 0.017
CCSD(T)                 2 0.019
CCSD(T)=FULL                 2 0.014
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.