Electron Interaction Energy Research Articles

Unveiling intermolecular mechanism and electronic properties between asphaltene and deep eutectic solvent for enhanced oil recovery using first principles calculation

Electronic structure and interaction energy calculations offer critical insights into non-bonded interactions in solute–solvent systems that can be used to extract heavy oil, particularly asphaltene, in enhanced oil recovery. The present study examines deep eutectic solvent (DES) interaction with asphaltene through first-principles calculations, revealing the role of hydrogen bonds, overall system stability, and its mechanism. The analysis reveals that the inclusion of asphaltene makes the DES-asphaltene structure less stable, i.e., increasing wettability with DES. DES formed non-bonded interactions with asphaltene's aliphatic segments but excluded aromatic rings due to strong π-π interactions. Among the studied DESs, DES1 (choline chloride and urea, 1:2 ratio) exhibited a strong interaction with asphaltene (-103.946 kJ/mol) and formed a hydrogen bond. All systems show negative binding energies, which indicate stability. Notably among them, DES2 (choline chloride and thiourea, 1:2) and DES3 (choline chloride and ethylene glycol, 1:2) displayed remarkable stability with asphaltene, evident in a widened band gap of 2.182 and 2.157 eV, respectively.

Comparative Analysis of Nickel-Phosphine Complexes with Cumulated Double Bond Ligands: Structural Insights and Electronic Interactions via ETS-NOCV and QTAIM Approaches.

This study presents a comprehensive analysis of nickel-phosphine complexes, specifically Ni(PH3)2(OCCH2), Ni(PH3)2(H2CCO), Ni(PH3)2(H2CCCH2), Ni(PH3)2(NNCH2), and Ni(PH3)2(η1-H2CNN). Utilizing ETS-NOCV analysis, we explored orbital energy decomposition and the Hirshfeld charges of the ligands, providing insights into the electronic structures and donor-acceptor interactions within these complexes. The interactions in the ketene and allene complexes exhibit similar deformation densities and NOCV orbital shapes to those calculated for Ni(PH3)2(NNCH2), indicating consistent interaction characteristics across these complexes. The total interaction energy for all η2 complexes is observed to be over 60 kcal/mol, slightly exceeding that of the analogous carbon dioxide complex reported earlier. Furthermore, the study highlights the stronger back-donation as compared to donor interactions across all η2 complexes. This is further corroborated by Hirshfeld analysis, revealing the charge distribution dynamics within the ligand fragments. The research offers new perspectives on the electron distribution and interaction energies in nickel-phosphine complexes, contributing to a deeper understanding of their catalytic and reactive behaviors.

Use quantum mechanical computational methods to investigate interactions between imidacloprid and boron nitride nanotubes

The study investigates the interaction between a boron nitride nanotube (BNNT) and an imidacloprid (IM) molecule. The structure of the BNNT is detailed, measuring 9.964 Å in diameter and 18.186 Å in length. Six interaction geometries (BNNT_IM_1 to BNNT_IM_6) between BNNT and IM are investigated, with BNNT_IM_6 showing the most thermodynamically stable interaction. The electronic interaction energies are calculated, and BNNT_IM_6 presents the lowest value (−1.89 eV), indicating a favorable interaction. Quantum theory of atoms in molecules (QTAIM) and analysis of noncovalent interactions (NCI) support the findings. BNNT_IM_6, with IM inside the nanotube, shows the highest electron sharing, explaining its superior stability. The chlorine-BNNT interaction was revealed to be a determining attractive component. The attraction/repulsion indices highlight BNNT_IM_1 as having the most attractive interaction, driven mainly by oxygen-BNNT and chlorine-BNNT interactions. The investigation emphasizes the importance of considering multiple factors, including electron density and interaction volume, in evaluating the strength of BNNT-IM interactions. This study model opens a proposal to assess the impact of functional groups, from a physicochemical perspective, of a molecule interacting with a nanotube surface.

Interactions and reactivity in crystalline intermediates of mechanochemical cyclorhodation reactions.

There is experimental evidence that solid mixtures of the rhodium dimer [Cp*RhCl2]2 and benzo[h] quinoline (BHQ) produce two different polymorphic molecular cocrystals called 4α and 4β under ball milling conditions. The addition of NaOAc to the mixture leads to the formation of the rhodacycle [Cp*Rh-(BHQ)Cl], where the central Rh atom retains its tetracoordinate character. Isolate 4β reacts with NaOAc leading to the same rhodacycle while isolate 4α does not under the same conditions. We show that the puzzling difference in reactivity between the two cocrystals can be traced back to fundamental aspects of the intermolecular interactions between the BHQ and [Cp*RhCl2]2 fragments in the crystalline environment. To support this view, we report a number of descriptors of the nature and strength of chemical bonds and intermolecular interactions in the extended solids and in a cluster model. We calculate formal quantum mechanical descriptors based on electronic structure, electron density, and binding and interaction energies including an energy decomposition analysis. Without exception, all descriptors point to 4β being a transient structure higher in energy than 4α with larger local and global electrophilic and nucleophilic powers, a more favorable spatial and energetic distribution of the frontier orbitals, and a more fragile crystal structure.

Detection of Aromatic Hydrocarbons in Aqueous Solutions Using Quartz Tuning Fork Sensors Modified with Calix[4]arene Methoxy Ester Self-Assembled Monolayers: Experimental and Density Functional Theory Study.

Quartz tuning forks (QTFs), which were coated with gold and with self-assembled monolayers (SAM) of a lower-rim functionalized calix[4]arene methoxy ester (CME), were used for the detection of benzene, toluene, and ethylbenzene in water samples. The QTF device was tested by measuring the respective frequency shifts obtained using small (100 µL) samples of aqueous benzene, toluene, and ethylbenzene at four different concentrations (10-12, 10-10, 10-8, and 10-6 M). The QTFs had lower limits of detection for all three aromatic hydrocarbons in the 10-14 M range, with the highest resonance frequency shifts (±5%) being shown for the corresponding 10-6 M solutions in the following order: benzene (199 Hz) > toluene (191 Hz) > ethylbenzene (149 Hz). The frequency shifts measured with the QTFs relative to that in deionized water were inversely proportional to the concentration/mass of the analytes. Insights into the effects of the alkyl groups of the aromatic hydrocarbons on the electronic interaction energies for their hypothetical 1:1 supramolecular host-guest binding with the CME sensing layer were obtained through density functional theory (DFT) calculations of the electronic interaction energies (ΔIEs) using B3LYP-D3/GenECP with a mixed basis set: LANL2DZ and 6-311++g(d,p), CAM-B3LYP/LANL2DZ, and PBE/LANL2DZ. The magnitudes of the ΔIEs were in the following order: [Au4-CME⊃[benzene] > [Au4-CME]⊃[toluene] > [Au4-CME]⊃[ethylbenzene]. The gas-phase BSSE-uncorrected ΔIE values for these complexes were higher, with values of -96.86, -87.80, and -79.33 kJ mol-1, respectively, and -86.39, -77.23, and -67.63 kJ mol-1, respectively, for the corresponding BSSE-corrected values using B3LYP-D3/GenECP with LANL2dZ and 6-311++g(d,p). The computational findings strongly support the experimental results, revealing the same trend in the ΔIEs for the proposed hypothetical binding modes between the tested analytes with the CME SAMs on the Au-QTF sensing surfaces.

Low energy electron interaction with citric acid: a local complex potential based time-dependent wavepacket study

Low energy electron interaction with citric acid: a local complex potential based time-dependent wavepacket study

Low to high energy electron interactions with AlCl

Low to high energy electron interactions with AlCl

Revealing a notable interaction in the binding of type II statins to HMG‐CoA reductase: Stacked cation–π interaction

AbstractThis study has centered on potentially important enzyme‐ligand interaction currently not incorporated: stacked cation–π interaction between the guanidinium group of arginine 590 residues in the HMG‐CoA reductase active site and the 4‐fluorophenyl group of type II statins. The geometry of interaction between these planar groups has been considered based on the X‐ray crystallographic structures already available in the protein data bank (PDB) archive. Electronic interaction energies between this residue and statins have been acquired by M06 and MP2 methods. In addition, stacking interaction and hydrogen bonding as two important investigated interactions are verified through prominent analyses: (1) quantum theory of atoms in molecules (QTAIM) analysis; (2) plotting and quantitative molecular surface analyses such as electrostatic potential (ESP) analysis, Hirshfeld surface (HS) and Becke surface (BS) analyses; (3) visual study methods such as noncovalent interaction (NCI), independent gradient model (IGM) analyses; and (4) localized orbital locator integrated pi over plane (LOLIPOP) index.The results indicate the absolute binding energy for type II statins is overall more than for type I statins.

Dopamine delivery systems based on C60 and C24 with B and N as substituents

Two different options as potential dopamine delivery systems were investigated in this study: fullerene C60- and C24-like structures. The systems being investigated include C60, C59X, C58X2, C24, C23X, and C22X2 (X represents B or N). Electron donor acceptor capacity and interaction energies were reported. Systems with one B are better electron acceptors than those with one N. The interaction of compounds containing B with dopamine is more favorable than the interaction of systems containing N. For a dopamine delivery system, at least two conditions are necessary. The first is the stability of the carrier-dopamine compound. This condition is fulfilled because C60-based heterofullerenes with B and dopamine form stable structures. Also, dopamine with C24-based structures containing B or N form stable structures. The second is that the interaction energy should be lower than the energy that binds dopamine to the receptor. Systems that fulfill the second condition include C60 and C58B2. The other systems present interaction energies that exceed 40 kcal/mol. Dopamine will bond to these systems and will most probably not be delivered at the receptor site, but these systems that interact strongly with dopamine may serve as agonists because they are good electron donors like dopamine. Systems with B could be antagonists of dopamine since they are good electron acceptors. This idea might be interesting to explore through experiments because heterofullerenes with B and dopamine might serve as antipsychotics rather than dopamine delivery systems.

A fluorescent receptor for alkylammonium ions based on an anthryl-linked triazole-modified hexahomotrioxacalix[3]arene

A novel C3-symmetrical anthracene-functionalized hexahomotrioxacalix[3]arene L was synthesized via Click chemistry and its chemosensing properties with alkylammonium ions were investigated. The significant fluorescence enhancements were observed with addition of alkylammonium ions (including primary and tertiary ones), indicating a high selectivity for alkylammonium ions. Our studies demonstrated that the detection limit on fluorescence response of the sensor to is in the 10–6 M range. The mechanism of the interaction between the L and alkylammonium ions has been investigated in detail by 1H NMR spectroscopic titration experiments. Density functional theory (DFT) quantum chemical calculations were conducted to estimate the electronic interaction energies (ΔIE) between the chemosensor L and alkylammonium ions.

The Effect of Counterions on the Detection of Cu2+ Ions in Aqueous Solutions Using Quartz Tuning Fork (QTF) Sensors Modified with L-Cysteine Self-Assembled Monolayers: Experimental and Quantum Chemical DFT Study

In this study, a sensing device employing a gold-coated quartz tuning fork (QTF) modified with a self-assembled monolayer (SAM) of L-cysteine was evaluated for the sensitive detection of Cu2+ ions in aqueous solutions. Three copper (II) salts, CuSO4, CuCl2, and Cu(NO3)2, at four different concentrations (10−12, 10−10, 10−8, and 10−6 M) in small (100 μL) water sample amounts were each used as analytes to investigate the influence of their counterions in the detection of the Cu2+ ions. It was found that, among the counterions, the sulfate anion had the largest effect upon the detection of Cu2+ in water, in the following order: SO42− > Cl− > NO3−. The lower limit of detection of the Cu2+ ions detected was in the 10−12 M range. The frequency shifts measured with the QTFs relative to deionized water were inversely proportional to the concentration/mass of the analytes. Density functional theory calculations were conducted to understand the effect of the counterions on the respective electronic interaction energies for the apparent host–guest binding of the analytes with L-cysteine and with gold surface-bound L-cysteine molecules. Gas phase (both with and uncorrected BSSE) and solution phase interaction energies (ΔIE) calculated at the B3LYP/LANL2DZ and ωB97XD levels of theory showed that the stability for the complexes were in the following order: [L-cysteine]⊃[CuSO4] > [L-cysteine]⊃[CuCl2] > [L-cysteine]⊃[Cu(NO3)2], which supports our experimental findings, as they were in the same order as the experimentally observed order for the copper salts tested: CuSO4 > CuCl2 > Cu(NO3)2.

Theoretical study on the structure and properties of Au⋯Au interlocking gold(i) thiolate[2]catenanes

To compare homoleptic [2]catenanes and single rings consisting of gold(i) thiolates, the geometric and electronic structures, absorption spectra, binding energy, interaction energy and composition of intramolecular forces were studied theoretically.

Detection of Volatile Alcohol Vapors Using PMMA-Coated Micromechanical Sensors: Experimental and Quantum Chemical DFT Analysis

Micromechanical sensors, in which the sensor response is created as a result of molecular interactions on the sensors’ surfaces, have been employed as a powerful technique for rapid and sensitive detection of low concentrations of chemical and biological materials. In the study reported herein, poly(methyl methacrylate) (PMMA)-coated microcantilever (MCL) sensors were used to detect the vapors of volatile alcohols (methanol, ethanol, and isopropanol) at three different concentrations. A vapor generator was used to generate and flow the alcohol vapor onto the PMMA coated MCL surface in a closed system chamber. The vapor adsorption onto the MCL surface results in a rapid and measurable deflection of the MCL. No significant deflections of the uncoated MCL occurred when the different vapors were passed through into the microcantilever chamber. Linear concentration–deflection responses were observed, with the highest sensitivity shown with methanol, followed by ethanol and then isopropanol. Density functional theory (DFT) quantum chemical calculations were conducted to estimate the electronic interaction energies (ΔIE) between the alcohol molecules and MMA and two different model tetrameric segments of PMMA. The computed ΔIEs were in the same order as the experimentally observed order: methanol > ethanol > isopropanol.

Effects of various metal doping on the structure and catalytic activity of CoB catalyst in hydrogen production from NaBH4 hydrolysis

Four ternary alloy CoB-based catalysts, including Co-Sn-B, Co-Mn-B, Co-Cr-B and Co-Bi-B, were prepared by chemical reduction method.The effect of Sn, Mn, Cr and Bi dopants on phase structure, surface morphologies, electronic interaction, catalytic activity and activation energies of CoB catalysts investigated in depth. Their catalytic activity in hydrogen production from NaBH4 hydrolysis was compared systematically. Compared with undoped CoB catalyst, it can be found that the doping of Cr and Bi exhibits a significant promoting effect on CoB catalyst by accelerating hydrogen generation rate. Nevertheless, the introduction of Sn and Mn into CoB catalyst only attains a slight increase in hydrogen production rate. The doping concentration of Sn, Mn, Cr, Bi species in CoB was adjusted to respectively check their phase structure and catalytic performance, indicating that there is an optimum doping concentration for each dopant. It can be concluded that the promoting effect of various dopants on catalytic performance can be attributed to crystalline phase, specific surface area and electronic interaction involved in NaBH4 hydrolysis.

UNIVERSAL EXPERIMENTAL FACILITY OF IHEPNP NSC KIPT FOR RESEARCH OF HIGH-ENERGY ELECTRON BEAM INTERACTION WITH THIN AMORPHOUS AND SINGLE-CRYSTAL STRUCTURES

The description and bench test results of the developed universal experimental facility [1] are presented. It mounted at the direct beam line of IHEPNP NSC KIPT 30 MeV Linac for the fundamental and applied research of high energy electron interaction with amorphous and single-crystal structures. The universal facility consists of the following structural elements and systems: electron beam transportation system; electron beam parameters formation and measurement, secondary electron emission monitor (SEM); electron beam full absorption Faraday cups (FC), collimators, goniometrical device system and magnetic energy analyzer.

Localized direct material removal and deposition by nanoscale field emission scanning probes

The manufactory of advanced micro- and nanoscale devices relies on capable patterning strategies. Focused electron beams, as for instance implemented since long in electron beam lithography and electron beam induced deposition, are in this regard key enabling tools especially at the early stages of device development and research. We show here that nanoscale field emission scanning probes can be potentially utilized as well for a prospective direct device fabrication by localized material deposition but notably, also by localized material removal. Field emission scanning probe processing was specifically realized on 10 nm chromium and 50 nm gold thin film stacks deposited on a (1 × 1) cm 2 fused silica substrate. Localized material deposition and metal removal was studied in various atmospheres comprising high vacuum, nitrogen, ambient air, naphthalene and carbon-dioxide. Stable and reliable regimes were in particular obtained in a carbonaceous atmosphere. Hence, localized carbon deposits were obtained but also localized metal removal was realized. We demonstrate furthermore that the selected electron emission parameters (20 V - 80 V, 180 pA) and the overall operation environment are crucial aspects that determine the degree of material deposition and removal. Based on our findings, direct tip-based micro- to nanoscale material patterning appears possible. The applied energy regime is also enabling new insights into low energy (< 100 eV) electron interaction. However, the underlying mechanisms must be further elucidated. • implementation of field-emission scanning probes to create localized 3D carbonaceous deposits from the gas phase. • demonstration of gold removal below the tip (line scans) by adjusting the experimental conditions. • first exploration of the impact of various atmospheres on the degree of material deposition and removal. • reproducible generation of line patterns by material removal and deposition.

Fragmentation-Based Decomposition of a Metalloenzyme-Substrate Interaction: A Case Study for a Lytic Polysaccharide Monooxygenase.

We present a novel decomposition scheme for electronic interaction energies based on the flexible formulation of fragmentation schemes through fragment combination ranges (FCRs; J. Chem. Phys., 2021, 155, 164105). We devise a clear additive decomposition with contribution of nondisjoint fragments and correction terms for overlapping fragments and apply this scheme to the metalloenzyme-substrate complex of a lytic polysaccharide monooxygenase (LPMO) with an oligosaccharide. By this, we further illustrate the straightforward adaptability of the FCR-based schemes to novel systems. Our calculations suggest that the description of the electronic structure is a larger error source than the fragmentation scheme. In particular, we find a large impact of the basis set size on the interaction energies. Still, the introduction of three-body interaction terms in the fragmentation setup improves the agreement to the supermolecular reference. Yet, the qualitative results for the decomposition scheme with two-body terms only largely agree within the investigated electronic-structure approaches and basis sets, which are B97-3c, DFT (TPSS and B3LYP), and MP2 methods. The overlap contributions are found to be small, allowing analysis of the interaction energy into individual amino acid residues: We find a particularly strong interaction between the substrate and the LPMO copper active site.

Interfacial interaction of parallel carbon nanotubes under external electric field: A first-principles study

Carbon nanotubes (CNTs) are widely used in high-quality and high-performance nanoscale devices. Using first-principles calculations, we studied the interaction at the interface between parallel CNTs with different electrical properties under applied transverse electric fields. Typical metallic armchairs (6,6) and semiconducting zigzag (10,0) CNTs were considered. The effect of axial moving of one of the CNTs on the interface electronic structure and interaction energy for different interface types was analyzed. Our calculations revealed that interfacial adhesion of CNTs increased with the increase of the external electric field. At this, the interface charge redistribution for (6,6) and (10,0) CNTs showed different polarization responses. By analyzing the density of states (DOS), a correlation between the semiconductor-to-metal transition in parallel (10,0) CNTs and interface interaction under applied external electric field was demonstrated. Obtained results provide a theoretical background for the application of the adhesion properties of CNTs in future nanoscale devices.

Micro- and nanoplastics retention in porous media exhibits different dependence on grain surface roughness and clay coating with particle size

The presence and/or coating of natural colloids (e.g., clays and metal oxides or hydroxides) on collector surfaces has frequently been demonstrated to enhance the retention of engineered colloids that are negatively charged due to favorable electrostatic interactions. However, this work demonstrates that the presence of natural clay coating can lead to reduced or nonmonotonic retention of micro- and nanoplastics (MNPs). Column experiments were carried out to systematically investigate the transport of MNPs with different sizes in relatively smooth and rough sands that had various clay coating fractions. These coating fractions on the collector were found to significantly influence MNP retention in a complex manner that changed with the colloid size and the roughness properties of the sand. This observation was attributed to the impact of clay coatings on the roughness and morphology properties of collector surfaces that were dominant over surface charge. Scanning electron microscopy and interaction energy calculations on surfaces with pillars or valleys indicate that mechanisms that contributed to MNP retention changed with the colloid size. In particular, retention of nanosized plastics was mainly controlled by interactions on convex/concave locations that changed with the solution chemistry, whereas microsized plastics were also strongly influenced by the applied hydrodynamic torque and straining processes. Additionally, the significant sensitivity of MNP retention under a low-level ionic strength also reflects the importance of roughness and charge heterogeneities. These observations are important for investigating the mechanisms of colloid transport in natural systems that ubiquitously exhibit clay coating on their surfaces.

Enhancement in non-linear optical properties of carbon nitride (C2N) by doping superalkali (Li3O): A DFT study

A systematized analysis of the electronic as well as the nonlinear optical properties of carbon nitride (C2N) doped with superalkali (Li3O) has been investigated through density functional theory (DFT) methods of B3LYP, LC-BLYP, and CAM-B3LYP at 6-31G (d,p) basis set. The FMOs value by the B3LYP method of DFT has been proved more promising to the experimental value of carbon nitride. So, it is employed as a more reliable method for computations. Doped molecules (M2 and M3) have a high interaction energy (-6.68 eV) and vertical ionization energy (3.46 eV), reduced energy gap in comparison with pure C2N indicating that designed complexes are more stable than pure C2N surface. The up-turn of UV absorption, dipole moment, and first hyperpolarizability have improved the electronic properties and interaction energies between the superalkali and carbon nitride after doping. The first hyperpolarizability and dipole moment of Li3O doped with pure surface has been increased up to 321,498 au and 5.31 D respectively. All results proved that Li3O doped with carbon nitride is a potential approach to synthesize the material by doping super alkali on carbon nitride for nonlinear optical devices.