The structure of zeolite clinoptilolite and the coordination of extraframework cations (Ca, Ba, Na and K) by framework oxygen atoms are examined by density functional theory (DFT) using two methods: the ONIOM two-layer model (DFT/MM) and periodic DFT. Both ONIOM and periodic model calculations predict correctly the clinoptilolite structure and find configurations with Al ? Si substitution at th...

Energy partitioning of pharmaceutical cocrystals by molecule-pair interaction and ONIOM energies identifies the driving force their formation, leading to in silico conformational sampling for predicting API-cocrystal combinations experiment.

The properties, interactions, and reactions of cyclic water clusters (H(2)O)(n=1-5) on model systems for a graphite surface have been studied using pure B3LYP, dispersion-augmented density functional tight binding (DFTB-D), and integrated ONIOM(B3LYP:DFTB-D) methods. Coronene C(24)H(12) as well as polycircumcoronenes C(96)H(24) and C(216)H(36) in monolayer, bilayer, and trilayer arrangements we...

A general procedure for quantum mechanics and molecular mechanics (QM/MM) studies on biochemical systems is outlined, and a collection of PERL scripts to facilitate ONIOM-type QM/MM calculations is described. This toolkit is designed to assist in the different stages of an ONIOM QM/MM study of biomolecules, including input file preparation and checking, job monitoring, production calculations, ...

Formaldehyde has been widely observed in the icy mantle of interstellar grains. H 2 CO may be formed from successive hydrogenations and further contribute to chemical complexity Interstellar medium (ISM) participating heterogeneous reactions with colliding gas phase atoms. Within this context, Eley-Rideal Langmuir-Hinshelwood rate constants formation on a formaldehyde doped amorphous water ice ...

Fourier transform infrared difference spectroscopy (FTIR DS) is widely used to study the structural details of electron transfer cofactors in photosynthetic protein complexes. In photosynthetic proteins quinones play an important role, functioning as a cofactor in light-driven electron transfer. In photosystem I (PS I) phylloquinone (PhQ) functions as an intermediary in electron transfer. To in...