Dual parameter smart sensor for nitrogen and temperature sensing based on defect-engineered 1T-MoS.

In general, defects are crucial in designing the different properties of two-dimensional materials. Therefore large variations in the electric and optical characteristics of two-dimensional layered molybdenum disulphide might be attributed to defects. This study presents the design of a temperature and nitrogen sensor based on few-layer molybdenum disulfide sheets (FLMS), which was developed from bulk MoS (BMS) through an exfoliation approach.

Lateral diffusion of ions near membrane surface.

Biological membranes isolate living cells from their environment, while allowing selective molecular transport between the inner and outer realms. For example, Na and K permeability through ionic channels contributes to neural conduction. Whether the ionic currents arise directly from cations in the bulk, or from the interface, is currently unclear.

External electric field to control the Diels-Alder reactions of endohedral fullerene.

The present work investigates the role of External Electric Field (EEF) on a Diels-Alder reaction of endohedral fullerene by means of chemical kinetics and quantum chemical calculations. The investigation suggests that by combining two strategies, first encapsulating the cation inside the fullerene followed by applying EEF, one can easily manipulate the energy barrier of the Diels-Alder reaction. To illustrate this general strategy, we have chosen the reaction of fullerene (C) and 1,3 cyclohexadiene, which is associated with a high energy barrier height of ∼11.

Nitrous acid (HONO) as a sink of the simplest Criegee intermediate in the atmosphere.

In the present work, we have investigated the reaction of nitrous acid with the simplest Criegee intermediate using chemical kinetics and quantum chemical calculations. It was found that reactions can occur through four different paths. Among them, one path involves hydrogen atom transfer and leads to the formation of hydroperoxymethyl nitrite, while two paths involve cycloaddition leading to the formation of ozonide and formic acid and the remaining path involves oxygen atom transfer leading to the formation of HNO as a final product.

Effect of microsolvation on the mode specificity of the OH˙(HO) + HCl reaction.

The present study investigates the mode specificity in the microsolvated OH˙(HO) + HCl reaction using on-the-fly direct dynamics simulation. To the best of our knowledge, this is the first study which aims to gain insights into the effect of microsolvation on the mode selectivity. Our investigation reveals that, similar to the gas phase OH˙ + HCl reaction, the microsolvated reaction is also predominantly affected by the vibrational excitation of the HCl mode, whereas the OH vibrational mode behaves as a spectator.

Oxidation of HOSO˙ by Cl˙: a new source of SO in the atmosphere?

In the present work, we have studied the formation of SO in the atmosphere from the oxidation of HOSO˙ by Cl˙ at the CCSD(T)/aug-cc-pV(+d)TZ//MP2/aug-cc-pV(+d)TZ level of theory. The present work reveals that the title reaction is a barrierless reaction that proceeds through a stable intermediate sulfurochloridous acid having a stabilization energy of ∼-56.5 kcal mol.

Effect of water on the oxidation of CO by a Criegee intermediate.

The present work employs the CCSD(T)/CBS//M06-2X/aug-cc-pVTZ level of theory to investigate the effect of a water monomer and dimer on the oxidation of carbon-monoxide by a Criegee intermediate (CH2OO). The present work suggests that in the presence of a water monomer the energy barrier of the title reaction reduced to ∼3.4 kcal mol-1 from the corresponding uncatalyzed barrier (∼12.

Kinetic instability of sulfurous acid in the presence of ammonia and formic acid.

In the present work, we have studied the effect of ammonia and formic acid on the kinetic stability of sulfurous acid using high level ab initio calculations. Our investigation reveals that the decomposition reaction of sulfurous acid becomes barrierless in the presence of both ammonia and formic acid. The half-life of the isolated sulfurous acid is estimated to be ∼20 days at room temperature, which becomes only ∼4.

OH + HCl Reaction at the Surface of a Water Droplet: An Ab Initio Molecular Dynamical Study.

The Born-Oppenheimer molecular dynamics (BOMD) simulation has been performed to investigate the dynamics of the OH + HCl reaction at the surface of a water droplet. The investigation suggests that the reaction occurred at the surface of the water droplet becomes almost 10 times faster than the corresponding gas-phase reaction. Besides, we have also performed the quantum mechanics/molecular mechanics calculation to calculate the unimolecular energy barrier of the reaction.

Effect of ammonia and formic acid on the CHO˙ + O reaction: a quantum chemical investigation.

In the present work, the catalytic effect of ammonia and formic acid on the CH3O˙ + O2 reaction has been investigated employing the MN15L density functional. The investigations suggest that, in the presence of ammonia, the reaction can proceed through two different pathways, namely a single hydrogen atom transfer and a double hydrogen atom transfer path, but due to the high energy barrier associated with the double hydrogen atom transfer channel, it prefers the single hydrogen atom transfer channel. On the other hand, in the case of formic acid, only the single hydrogen atom transfer path is found to be feasible.

Switching of the reaction enthalpy from exothermic to endothermic for decomposition of HCO under confinement.

Various size fullerenes (C, C and C) have been used as a means of confinement to study the decomposition reaction of carbonic acid alone as well as in the presence of a single water molecule in a confined environment. Quantum chemical calculations reveal that as the effect of confinement increases by reducing the size of the fullerene cage, the bare reaction switches from exothermic to endothermic gradually. As a result, the equilibrium of the reaction shifts toward the reactant side, which suggests that the decomposition of carbonic acid becomes thermodynamically disfavored under confinement.

Revisiting the reaction energetics of the CHO˙ + O (Σ) reaction: the crucial role of post-CCSD(T) corrections.

The CHO˙ + O reaction has been studied by means of high level ab initio calculations to predict the reaction energy and barrier height with chemical accuracy. We have employed post-CCSD(T) corrections in terms of partial quadratic excitations at the coupled cluster level, along with relativistic, core, spin-orbit and diagonal Born-Oppenheimer corrections, to estimate the barrier height and energetics for the title reaction. After including all the corrections, the reaction energy and barrier height were found to be -26.

Impact of Post-CCSD(T) Corrections on Reaction Energetics and Rate Constants of the OH + HCl Reaction.

High level ab initio calculations have been performed to predict the reaction energy and barrier height for the OH + HCl reaction. After including the effect of full quadratic excitations at the coupled cluster level, in addition to core, relativistic, spin-orbit, and diagonal Born-Oppenheimer corrections, we found the values of reaction energy and barrier height to be -15.29 and +2.

Ammonolysis of ketene as a potential source of acetamide in the troposphere: a quantum chemical investigation.

Quantum chemical calculations at the CCSD(T)/CBS//MP2/aug-cc-pVTZ levels of theory have been carried out to investigate a potential new source of acetamide in Earth's atmosphere through the ammonolysis of the simplest ketene. It was found that the reaction can occur via the addition of ammonia at either the C[double bond, length as m-dash]C or C[double bond, length as m-dash]O bond of ketene. The potential energy surface as well as calculated rate coefficients indicate that under tropospheric conditions, ammonolysis would occur almost exclusively via ammonia addition at the C[double bond, length as m-dash]O bond with negligible contribution from addition at the C[double bond, length as m-dash]C bond.

Effect of Ammonia and Formic Acid on the OH + HCl Reaction in the Troposphere: Competition between Single and Double Hydrogen Atom Transfer Pathways.

Quantum chemical calculations at QCISD and CCSD(T) levels of theory have been performed to investigate the effect of NH and HCOH on the reaction between OH and HCl. Potential energy profiles indicate that both NH and HCOH catalyzed reactions could proceed through two different channels, namely, single and double hydrogen atom transfer. Theoretically calculated rate constants for both the catalysts show that both NH and HCOH catalyzed channels prefer a single hydrogen atom transfer path.

Isomerization of methoxy radical in the troposphere: competition between acidic, neutral and basic catalysts.

A comprehensive investigation of the roles of acidic, neutral and basic catalysts in isomerization of methoxy radical in the troposphere has been carried out by quantum chemical calculations at the MP2 and CCSD(T) levels of theory. The effect of basic catalysts, namely ammonia and an ammonia-water complex, on the isomerization process has been studied for the very first time. In terms of rate coefficients ammonia was found to be a better catalyst than a water monomer whereas the ammonia-water complex was found to be more efficient over a water dimer but marginally less efficient than formic acid.