Theoretical investigations of the IR spectroscopy of Ni(C(2)S(2)H(2))(2). A case study of the P_VMWCI(2) algorithm including anharmonic effects.

The near infrared (NIR) spectra of bis(ethylene-1,2-dithiolato)nickel, Ni(C(2)S(2)H(2))(2) are fully interpreted here by applying a method developed for efficient automatic computation of both the infrared wave numbers and the intensities. The employed procedure uses parallel variational multiple window configuration interaction wave functions, the so-named P_VMWCI(2) algorithm, which incorporates both the mechanical and the electric anharmonic effects. It is shown that inclusion of anharmonicities is crucial for correctly assigning the fundamental, combination, and overtone vibrational frequencies in the infrared spectrum of the target system, for which conflicting assignments are found in literature.

Linear and nonlinear optical properties of a series of Ni-dithiolene derivatives.

Some linear and nonlinear optical (NLO) properties of Ni(SCH)(4) and several of its derivatives have been computed by employing a series of basis sets and a hierarchy of methods (e.g., HF, DFT, coupled cluster, and multiconfigurational techniques).

Is it possible to determine rigorous magnetic Hamiltonians in spin s = 1 systems from density functional theory calculations?

The variational energies of broken-symmetry single determinants are frequently used (especially in the Kohn-Sham density functional theory) to determine the magnetic coupling between open-shell metal ions in molecular complexes or periodic lattices. Most applications extract the information from the solutions of m(s)(max) and m(s)(min) eigenvalues of S(z) magnetic spin momentum, assuming that a mapping of these energies on the energies of an Ising Hamiltonian is grounded. This approach is unable to predict the possible importance of deviations from the simplest form of the Heisenberg Hamiltonians.

DFT modeling of sandwich complexes involving cationic palladium chains and polyenic or polycyclic aromatic hydrocarbons.

DFT calculations are reported on a series of one-dimensional palladium complexes with general formula [Pd(m)(C(2n)H(2n+2))(2)](2+) (m = 2-4, n = 2-8, n > or = m), in order to model and analyze the bonding in the series of organometallic sandwich compounds recently reported by the group of T. Murahashi and H. Kurosawa.