National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 22May 2022
NIST Standard Reference Database 101
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III.G.10.a.

Energy differences between frozen core and all electrons correlated.
MP2, MP3, MP4, B2PLYP, CCSD, and CCSD(T)

For C4H4 (cyclobutadiene)

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
Moller Plesset perturbation MP2=FULL -0.001716 -0.006552 -0.006552 -0.005230 -0.019077 -0.019720 -0.020100 -0.074157 -0.074820 -0.029114 -0.067647 -0.009542 -0.060450 -0.110473 -0.010958 -0.071109 -0.113525
MP3=FULL         -0.018878   -0.034115                    
MP4=FULL   -0.006285     -0.018946       -0.078291     -0.008972 -0.062763   -0.010385 -0.074319  
Coupled Cluster CCSD=FULL         -0.018640           -0.070795 -0.008756 -0.062078   -0.010144    
CCSD(T)=FULL         -0.018896           -0.071316 -0.008913 -0.062647   -0.010318 -0.074177  
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