DK-CCSD

Table 8 shows scalar-relativistic and spin-orbit coupled Rg, g, and Dg values for (113 )H and (113 )F, respectively, as another example of comparison between RECP and all-electron calculations. The size of the basis sets and the core for (113) RECP are the same as for (117)H [75]. Seth et a/. s all-electron DK-, DC-based results [78] are included for comparison. It is noted that DK-CCSD(T) Dg values for (113)H and (113)F were not directly evaluated, and the approximated DK-CCSD(T) Dg value for (113)H seems to be too small. The REP values dif-... 

Pd was found to form a covalent T -bond [114] with the graphene sheet. PBE considerably overestimates (-27.3kcalmoH ) as compared to DK-CCSD(T)/ANO-RCC-VTZP in the benchmark on benzene (—19.7kcalmol ). However, in this study only valence-shell electrons were correlated, so it should... 

Diffuse augmented basis sets were also developed for both the NR and DK cases by simple even tempered extensions. Valence electrons correlated CCSD(T) dipole polarizabilities calculated with the inclusion of DK scalar relativity are 35.08 and 35.07 a.u. for aug-cc-pVQZ-DK and aug-cc-pV5Z-DK, respectively. These values are about 0.3 a.u. larger than the PP values and therefore somewhat further away from experiment. 

Table I. CCSD(T) spectroscopic constants calculated for the 11 state of YC using the new ECP-based cc-pVnZ-PP (V/tZ-PP) and all-electron cc- pVQZ (-NR and -DK) basis sets for Y and cc-pV/fZ for C...

Table III. Spectroscopic constants of X L HgH from all-electron CCSD(T) calculations both with (DK) and without (NR) the approximate inclusion of scalar relativistic effects"...

Computer programs were MOLCAS 3 program system (25) for SCF, CASSCF, and CASPT2 calculations and the program TITAN for closed shell calculations (26). The new version of the COMENIUS program was used for open shell CCSD(T) calculations based on the spin adapted singly and doubly excited amplitudes (15, 27-29). These codes were supplemented by the generator of the no-pair hamiltonian written by B. A. Hess in all DK calculations. 

The dipole moment curves are presented in Figures 2-4. The positive sign of the dipole moment means the polarity B(+)Me(-). The relativis-tically calculated CASPT2-DK curves differ considerably from their nonrelativistic counterparts. Moreover, the CASPT2-DK and CCSD(T)-DK... 

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... 

The spin-orbit changes in bond lengths for (114)H [98] and (117)H [104] estimated by spin-orbit Cl calculations are somewhat smaller compared to CCSD(T) calculations, although the same RECPs and basis sets of similar quality were used for the elements 114 and 117. The bond length contraction for (113)H at the spin-orbit Cl level is also smaller compared to our all-electron DK/DHF-CCSD(T) results [78]. 

Effective level of QClSD(T,fuU) QCISD(T,FC1) QCISD(T.FCI) CCSD-DK(XFCl) CCSD-DK(T,FC1)... 

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