Monika Musial

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The intermediate Hamiltonian multireference coupled-cluster (CC) method with singles, doubles, and triples within the excited (1,1) sector of Fock space (FS) is implemented and formulated to calculate excitation energies (EEs). Due to the intermediate Hamiltonian formulation, which provides a robust computational scheme for solving the FS-CC equations,(More)
The multireference Fock-space coupled-cluster (FS-CC) equations constructed via the effective Hamiltonian approach are reduced to those obtained through a partitioning technique for the matrix diagonalization. This allows finding a better route to solve the FS-CC equations for the (1,1) sector by the direct diagonalization of the properly constructed(More)
The recently reported inclusion of the connected triples into the intermediate Hamiltonian realization of the Fock space coupled-cluster (IH-FS-CC) theory [M. Musial and R. J. Bartlett, J. Chem. Phys. 129, 044101 (2008)] is extended to produce the triplet states. This is done entirely in spatial orbitals on the basis of the double occupancy in the(More)
Several levels of theory, including both Gaussian-based and plane wave density functional theory (DFT), second-order perturbation theory (MP2), and coupled cluster methods (CCSD(T)), are employed to study Au6 and Au8 clusters. All methods predict that the lowest energy isomer of Au6 is planar. For Au8, both DFT methods predict that the two lowest isomers(More)
A description of flake orientation in OSB is presented by means of standard distribution cut at the length interval π. The root of variance of this distribution is indicated as the parameter which characterizes the degree of flake orientation. Using the anisotropy of microwave attenuation caused by wood, a non-destructive method of determining this(More)
We consider classes of noniterative (∼n(7)) ΛCCSD(TQ(f)) (coupled cluster singles and doubles with noniterative triples and quadruples) for bond breaking including approximations based on Λ(2)CCSD(TQ(f)). All methods are applied to the standard tests for the treatment of potential energy curves for small molecules (HF, F(2), H(2)O, N(2), and C(2)) where(More)
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