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Swart M.,Institute Of Quimica Computacional I Catalisi Iqcc | Swart M.,Catalan Institution for Research and Advanced Studies
Chemical Physics Letters | Year: 2013

A new family of (range-separated) hybrid functionals is presented that corrects several of the shortcomings of the recently reported SSB-D functional. The new functionals include Grimme's D3 dispersion energy, contain a reduced number of parameters which have been optimized against a number of different interaction types. When comparing the new functionals with over thirty other density functionals, the new hybrid functional S12h and its range-separated analogue CAM-S12h are found to be the best performing ones for the different interaction types. The performance for spin states is poor for the hybrid functionals, but very well for the GGA counterpart S12g. © 2013 Elsevier B.V. All rights reserved.

Cioslowski J.,University Of Szczecin | Strasburger K.,Wroclaw University of Technology | Matito E.,Institute Of Quimica Computacional I Catalisi Iqcc
Journal of Chemical Physics | Year: 2014

For a wide range of confinement strengths ω, explicitly-correlated calculations afford approximate energies E(ω) of the ground and low-lying excited states of the four-electron harmonium atom that are within few μhartree of the exact values, the errors in the respective energy components being only slightly higher. This level of accuracy constitutes an improvement of several orders of magnitude over the previously published data, establishing a set of benchmarks for stringent calibration and testing of approximate electronic structure methods. Its usefulness is further enhanced by the construction of differentiable approximants that allow for accurate computation of E(ω) and its components for arbitrary values of ω. The diversity of the electronic states in question, which involve both single- and multideterminantal first-order wavefunctions, and the availability of the relevant natural spinorbitals and their occupation numbers make the present results particularly useful in research on approximate density-matrix functionals. The four-electron harmonium atom is found to possess the 3P+ triplet ground state at strong confinements and the 5S- quintet ground state at the weak ones, the energy crossing occurring at ω ≈ 0.0240919. © 2014 AIP Publishing LLC.

Font M.,Institute Of Quimica Computacional I Catalisi Iqcc | Font M.,University of Girona | Ribas X.,Institute Of Quimica Computacional I Catalisi Iqcc | Ribas X.,University of Girona
Topics in Organometallic Chemistry | Year: 2015

Pincerlike cyclic ligands have overcome the high instability of transition metals in their higher oxidation states and have permitted the isolation of such species and the exhaustive study of their properties and reactivity. The formation and isolation of organometallic CuII and MIII (M¼Cu, Ag, Au) complexes stabilized by NCPs, carbaporphyrins, carbaporphyrinoids, heterocalixarenes, and triaza macrocyclic ligands will be discussed in this chapter. The study of these complexes have led to the discovery of unprecedented reactivity and proved the plausibility of often invoked pathways in copper-catalyzed cross-coupling reactions. Aryl-MIII (M¼Cu, Ag) stable species have been implicated as the key intermediate species that operate in coupling catalysis through two-electron redox cycles involving oxidative addition and reductive elimination fundamental steps. © Springer International Publishing Switzerland 2015

Reis H.,National Hellenic Research Foundation | Luis J.M.,Institute Of Quimica Computacional I Catalisi Iqcc | Garcia-Borras M.,Institute Of Quimica Computacional I Catalisi Iqcc | Kirtman B.,University of California at Santa Barbara
Journal of Chemical Theory and Computation | Year: 2014

Previously, a treatment of the vibrational contribution to nonlinear optical properties for molecules with large amplitude modes in a symmetric double-minimum potential well was devised. The vibronic energies were written as a power series in the field for two limiting cases of the ratio between the field-induced energy and the zero-field splitting energy of the two lowest vibronic states. This treatment is extended here to include all values of the ratio and also an asymmetric double-well potential. It is shown that a consistent treatment of NLO effects in the general case leads to new field expansion coefficients, which are formulated in terms of the usual dipole moment and (hyper)polarizabilities. As an example, the new treatment is applied to the inversion motion of CH3-. © 2013 American Chemical Society.

Gruden-Pavlovic M.,University of Belgrade | Stepanovic S.,University of Belgrade | Peric M.,University of Belgrade | Guell M.,Institute Of Quimica Computacional I Catalisi Iqcc | And 2 more authors.
Physical Chemistry Chemical Physics | Year: 2014

Density Functional Theory (DFT) was used to analyse and explain spin state energetics of first-row transition metals (MnII, FeII, CoII; CrIII, MnIII, FeIII, Co III; MnIV) in polypyrazolylborato complexes. We explored the effects of substitutions at the 3 and 5 positions of the pyrazolyl rings, as well as the influence of Jahn-Teller (JT) distortions on spin-state switching. Although the stabilizations due to JT distortion are sometimes substantial, this does not lead to switching of the spin ground-state. On the other hand, electron withdrawing or donating substituents do lead to significant changes in the spin-crossover (SCO) properties of the investigated complexes. © the Partner Organisations 2014.

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