Equation-of-motion coupled-cluster singles and doubles

The partitioned equation-of-motion second-order many-body perturbation theory [P-EOM-MBPT(2)] [67] is an approximation to equation-of-motion coupled-cluster singles and doubles (EOM-CCSD) [17], which will be fully described in Section 2.4. The EOM-CCSD method diagonalizes the coupled-cluster effective Hamiltonian H = [HeTl+T2) in the singles and doubles space, i.e.,... 

One-bond X-Y couplings have been computed by Del Bene et for 18 HmX-YHn molecules, with X = C, N and P, using the equation-of-motion coupled-cluster singles and doubles method. The ealculated values cover the range from ca. 200 Hz in acetylene to ca. -450 Hz in -diphosphene. However, in the latter case agreement between the experimental and calculated values is rather poor. The same applies to some other molecules, such as, for example, methyl phosphine for which the calculated and experimental J values are 0.8 and 9.3 Hz, respectively. 

Kus, T, Lotrich, V E, and Bartlett, R. J. (2009). Parallel implementation of the equation-of-motion coupled-cluster singles and doubles method and application for radical adducts of cytosine, J. Chem. Phys. 130, p. 124122, doi 10.1063/1.3091293. 

Spin-spin coupling constants were evaluated using the equation-of-motion coupled cluster singles and doubles (EOM-CCSD) method in the Cl (configuration interac-tion)-like approximation [52, 53], with all electrons correlated. For these calculations, the Ahlrichs [54] qzp basis set was placed on and F, and the qz2p basis... 

Ab initio equation of motion coupled cluster singles and doubles (EOM-CCSD) calculations of spin-spin couplings have been performed by Del Bene et for F-F and FI F couplings in cyclic FEI polymers (FEI)n, n = 2-6. The authors conclude that although both the Fermi contact term and VpF couplings increase and become positive when the cluster size increases, the FC term is not a good quantitative approximation to /ff-... 

One-Bond Coupling Constants in Monomers and Hydrogen-Bonded Complexes. - Del Bene and Elguero carried out ab initio calculations of SSCCs at the equation-of-motion coupled cluster singles and doubles (EOM-CCSD) level of theory to investigate one-bond C- H, and F- H... 

The symmetry-correct anion orbitals can also be utilized in calculations of states of the N03 cation. The primary purpose of this work is to examine the NO3 ionization spectrum and the ground and low excited states of the N03 cation system by the DIP-STEOM-CCSD method (40) (double ionization potential similarity transformed equation-of-motion coupled-cluster singles and doubles). The DIP-STEOM-CCSD method is built upon the IP-EOM-CCSD method (32) (ionization potential equation-of-motion coupled-cluster singles and doubles), which in turn, has been shown to be equivalent (41,42) to singly ionized FSMRCC, such as the example of Kaldor above. The DIP-STEOM-CCSD method generates ground and excited states of the cation by deletion of... 

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