CCSD calculations benchmark testing

Ejt = l,463cm ) are considered to be benchmark results for the determination of the JT parameters. They also identitied three dominant normal modes necessary to explain their results. These were recently confirmed by Stanton et al. using Equation-of-motion ionization potential coupled-cluster (EOMIP-CCSD) calculations [45]. Thus, this system is a good test case for both our multideterminental DFT approach in studies of the JT effect and for our model of the analysis of the multimode JT effect. 

Full configuration interaction (Cl) calculations for the shieldings in H2 (50) and BH molecules have demonstrated that the CCSD(T) results are sufficiently close to the full Cl results, so that for practical purposes, the CCSD(T) calculations may be considered as the benchmark calculations for each molecule, against which other methods such as density functional methods may be tested. 

Recently, molecular calculations were performed for simple compounds of element 111 at various levels of theory [95,116]. The electronic structure of the simplest molecule lllH, used as a test system for benchmark calculations similar to AuH, was studied in detail with the use of various methods (HF, DF, DK, PP, PP CCSD(T), DFT, BDF, etc.). Results are compared in Table 9 demonstrating the importance of both relativistic and correlation effects. (A more extended table can be found in [26,95]). A comparison of the relativistic (DF or ARPP) with the nonrelativistic (HF or NRPP) calculations shows that... 

As a benchmark set for the quantitative validation of dispersion corrections, Hobza and coworkers suggested the S22 set (Jurecka et al. 2006), which contains 22 weakly bonded dimers. This S22 benchmark set provides interaction energies of hydrogen-bonded, dispersion-bonded and mixed complexes, which are the calculated results of the CCSD(T) method at the complete basis set (CBS) limit (Riley et al. 2010). Due to its convenience, this benchmark set has been used not only in testing the accuracies of dispersion corrections but also in determining the adjustable parameters of semiempirical dispersion-corrected functionals. Table 6.1 displays the mean absolute deviations (MAD) of various dispersion-corrected DPT calculations for the S22 benchmark set in ascending order. This table shows clearly that, independent of the dispersion corrections combined, the LC-tvdW methods... 

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