High-Spin Blatter's Triradicals.

Robust organic triradicals with high-spin quartet ground states provide promising applications in molecular magnets, spintronics, In this context, a triradical based on Blatter's radical has been synthesized recently, having two low-lying non-degenerate doublet states with a quartet ground state. The traditional broken-symmetry (BS)-DFT computed doublet-quartet energy gaps are reported to be somewhat overestimated in comparison to the experimentally observed values. In this work, we have employed different methods on this prototypical system to obtain more accurate doublet-quartet energy gaps for this triradical.

Toward an efficient implementation of internally contracted coupled-cluster methods.

A new implementation of the internally contracted multireference coupled-cluster with singles and doubles (icMRCCSD) method is presented. The new code employs an efficient tensor contraction kernel and can also avoid full four-external integral transformations, which significantly extends the scope of the applicability of icMRCCSD. The new implementation is currently restricted to the simple case of two active electrons in two orbitals and also supports the computation of spin-adapted doublet and triplet coupled-cluster wavefunctions.

Photochemistry of 3,6-Didehydropyridazine Biradical─An Untraceable Benzyne Analogue.

We report matrix isolation infrared spectroscopic studies to characterize 3,6-didehydropyridazine , a heterocyclic analogue of benzyne, combined with computations. In this regard, we have utilized 3,6-diiodopyridazine as a photolytic precursor. The experiments toward the generation of the biradical are carried out in argon and nitrogen matrices at 4 K.

Potential Energy Curves of Molecular Nitrogen for Singly and Doubly Ionized States with Core and Valence Holes.

Theoretical description of potential energy curves (PECs) of molecular ions is essential for interpretation and prediction of coupled electron-nuclear dynamics following ionization of parent molecule. However, an accurate representation of these PECs for core or inner valence ionized state is nontrivial, especially at stretched geometries for double- or triple-bonded systems. In this work, we report PECs of singly and doubly ionized states of molecular nitrogen using state-of-the-art quantum chemical methods.

Beyond Born-Oppenheimer constructed diabatic potential energy surfaces for F + H reaction.

First principles based beyond Born-Oppenheimer theory has been implemented on the F + H system for constructing multistate global diabatic Potential Energy Surfaces (PESs) through the incorporation of Nonadiabatic Coupling Terms (NACTs) explicitly. The spin-orbit (SO) coupling effect on the collision process of the F + H reaction has been included as a perturbation to the non-relativistic electronic Hamiltonian. Adiabatic PESs and NACTs for the lowest three electronic states (1A', 2A', and 1A″) are determined in hyperspherical coordinates as functions of hyperangles for a grid of fixed values of the hyperradius.