Theoretical approach towards accurate molecular interactions with low dimensional substrates

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Tuning dissociation using isoelectronically doped graphene and hexagonal boron nitride: water and other small molecules

Novel uses for 2-dimensional materials like graphene and hexagonal boron nitride (h-BN) are being frequently discovered especially for membrane and catalysis applications. Still however, a great deal remains to be understood about the interaction of environmentally and industrially elevant molecules such as water with these materials. Taking inspiration from advances in hybridising graphene and h-BN, we explore using density functional theory, the dissociation of water, hydrogen, methane, and methanol on graphene, h-BN, and their isoelectronic doped counterparts: BN doped graphene and C doped h-BN. We find that doped surfaces are considerably more reactive than their pristine counterparts and by comparing the reactivity of several small molecules we develop a general framework for dissociative adsorption. From this a particularly attractive consequence of isoelectronic doping emerges: substrates can be doped to enhance their reactivity specifically towards either polar or non-polar adsorbates. As such, these substrates are potentially viable candidates for selective catalysts and membranes, with the implication that a range of tuneable materials can be designed

Interactions between large molecules pose a puzzle for reference quantum mechanical methods

Quantum-mechanical methods are used for understanding molecular interactions throughout the natural sciences. Quantum diffusion Monte Carlo (DMC) and coupled cluster with single, double, and perturbative triple excitations [CCSD(T)] are state-of-the-art trusted wavefunction methods that have been shown to yield accurate interaction energies for small organic molecules. These methods provide valuable reference information for widely-used semi-empirical and machine learning potentials, especially where experimental information is scarce. However, agreement for systems beyond small molecules is a crucial remaining milestone for cementing the benchmark accuracy of these methods. We show that CCSD(T) and DMC interaction energies are not consistent for a set of polarizable supramolecules. Whilst there is agreement for some of the complexes, in a few key systems disagreements of up to 8 kcal mol−1 remain. These findings thus indicate that more caution is required when aiming at reproducible non-covalent interactions between extended molecules

THE METABOLIC DISTURBANCES AS THE INDICATOR OF THE HARMFUL ACTION OF THE INDUSTRIAL POISONS IN THE PROBLEM OF THE PROPHYLACTIC TOXICOLOGY

The objects of investigation: 17 chemical substances, relating to the different classes of the compounds (the derivatives of hydrazine, amino butane acid, amino nitriles and others) in the experiments performed on the minor laboratory animals. The work is aimed at studying the biological role of the xenobiotics metabolism processes in the development of the pathology and formation of the organism adaptation reactions for the needs of the theory and practice of hygiene. For the first time, the conception about the obligatory interaction (direst or indirect) of the most of chemical substances, getting in the organism with the system of the microsomal MOG, has been formulated. Theoretically and experimentally justified has been the role of the microsomal oxydation as the most important mechanism of the biochemical adaptation to the poison effect. The obtained results contribute to the objective evaluation of the industrial poisons and medicine means real danger with its acute and chronic entering the organism, they allow to consider and prognose the character of its combined action. The materials have been used in justification of the hygienic regulations. The MPC for the operating zone air for 13 chemical substances, the methodical recommendations have been justified and approved by the USSR Health Ministry. The field of application: the medicine, sanitary, the chemical and pharmacological industryAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio