International Journal of Quantum Chemistry

An evolutionary algorithm-based method to sample the important part of the Hilbert space in strongly correlated systems is developed as an alternative to stochastic approaches like MCCI, FCI-QMC, DMRG, and ACI. This method has the ability to capture both static and dynamic correlation, with excellent performance and convergence properties, when tested against the N₂ triple bond breaking problem. The genetic algorithm accelerates the search of important configurations in the full configuration space.

Halogen bonding plays an important role in liquid crystals, polymerization, crystal engineering, and biomedical applications. This interaction can be tuned systematically to design novel materials and pharmaceutical ligands with specifically desired properties. First-principles calculations show how to use of V_s,max and heterolytic bond breaking energy as a tool to tune the strength of σ-hole and N···Cl halogen bonds.

First-principles calculations provide valuable insight into the mechanism of the reactions between phenol and hydroxyl radical. Under aqueous environment reaction modeling reveals the antioxidant characters of phenolic compounds. Transition states involving proton transfers for elementary processes were determined for this class of reactions by density functional theory calculations.

Esters are important intermediates in the chemical industry due to their widespread pharmaceutical applications and biodiesel production. Extensive experimental studies have been dedicated to the esterification reactions from carboxylic acids and acid halides, and Density Functional Theory (DFT) calculations can play an important role in clarifying their mechanisms. DFT-based quantum descriptors are, in fact, used to provide better understanding of the reactivity, selectivity, and stability of this class of reactions.

This contribution reviews quantum dynamical studies of ultrafast charge separation in organic donor-acceptor materials developed for photovoltaics applications, with a special focus on the role of molecular packing and vibronic interactions. An accurate picture of the coherent femtosecond-scale events is obtained by combining first-principles parametrized model Hamiltonians, based upon TDDFT and/or high-level electronic structure calculations, with high-dimensional quantum dynamics using the Multi-Configuration Time-Dependent Hartree (MCTDH) method.