Basis-set extrapolation

CCSD(T)/6-31G(d)//B3LYP/6-31G d), basis set extrapolation to 6-311G(d,p) at MP2 level, ZPE correction at B3LYP/6-31G(d) level, no thermal corrections. 

We will concentrate on Gaussian-type and CBS methods, because these have been the most widely-used and have thus accumulated an archive of results, are the most accessible, and because several versions of them are available. However, there are other high-accuracy multistep methods, such as the Weizmann procedures of Martin and de Oliveira, W1 and W2 [188], and of Boese et al., W3 and W4 [189], which like the CBS methods are based on basis set extrapolation. W1 and W2 have a mean absolute deviation of about 1 kJ mol 1 (not 1 kcal mol-1), and incorporate relativistic effects, and W2 has no empirical parameters, unlike the Gaussian and CBS methods. W3 and W4 methods have similar errors to W1 and W2, and the authors speculate on the reasons for the obstinate 0.1 kcal/mol barrier . These very accurate methods are still limited molecules of about or less than the reach of CBS-APNO. 

M.R de Lara-Castells, et at, Complete basis set extrapolation limit for electronic structure calculations Energetic and nonenergetic properties of HeBr and HeBr2 van der Waals dimers, /. Chem. Phys. 115 (22) (2001) 10438-10449. 

Complete basis set extrapolation at RI-MP2 with CCSD(T) correction. 

Geometry optimized at R1-MP2/TZVPP, energy from a complete basis set extrapolation with CCSD(T) correction, Ref 115. 

HNSiC lies 138kJmoP above it (UCCSD/infinite basis set extrapolation//B3LYP/6-31 lG(d,p) level). The triplet... 

Modified Neglect of Diatomic Overlap Parametric Method Number 3 (MNDO-PM3) 3.10.6 The MNDO/d Method 88 89 5.5 5.6 5.4.5 Correlation Consistent Basis Sets Extrapolation Procedures Isogyric and Isodesmic Reactions 162 164 169... 

Application area 4 basis set extrapolation and the calibration 242 of general energy models... 

Mackie, 1. D., and DiLabio, G. A. (2011]. Approximations to complete basis set-extrapolated, highly correlated non-covalent interaction energies,/. Chem. Phys. 135, p. 134318, doi 10.1063/1.3643839. 

For meta-benzyne, given that methods in Table 9 have not performed a basis set extrapolation, one may reasonably beheve that all of the proposed methods may change by 2 kcal/mol. The DEA-CCSD value is basis set... 

---