Article
Chemistry, Physical
Ira Litvak, Avner Cahana, Yaakov Anker, Sharon Ruthstein, Haim Cohen
Summary: Diamonds contain stable carbon radicals and exposure to polishing or high temperatures affects the concentration and structure of these radicals, resulting in the emission of orange light. Research shows that the polishing process has more effects on the paramagnetic centers than just thermal heating.
Article
Materials Science, Multidisciplinary
Marya Ivanovskaya, Katsiaryna Chernyakova, Evgeni Ovodok, Sergey Poznyak, Dzmitry Kotsikau, Igor Azarko
Summary: EPR spectroscopy was used to study the role of defects in black titanium dioxide nanotubes. Amorphous carbon was found to contribute to the deep black color of anatase-type TiNTs. The orientation of graphite-like networks along the growth direction of the nanotubes was revealed by analyzing EPR spectra with different magnetic field axis orientations.
MATERIALS CHEMISTRY AND PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Anna M. Ferrari, Khaled E. El-Kelany, Francesco S. Gentile, Maddalena D'Amore, Eleonora Romeo, Roberto Dovesi
Summary: The spin density function and hyperfine coupling constants of the NV- defect in its triplet ground state were computed using complex computational methods, including simulations of charged defects. The results were in good agreement with recent experimental results, showing a closer quantitative match to experiment than previous theoretical studies.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2022)
Article
Chemistry, Multidisciplinary
Rohan Pokratath, Dietger Van den Eynden, Susan Rudd Cooper, Jette Katja Mathiesen, Valerie Waser, Mike Devereux, Simon J. L. Billinge, Markus Meuwly, Kirsten M. O. Jensen, Jonathan De Roo
Summary: This paper investigates the reaction mechanism of synthesizing colloidal zirconia and hafnia nanocrystals using metal chloride and metal isopropoxide. The active precursor species and the interaction between the surfactant and the precursors are identified through nuclear magnetic resonance spectroscopy, density functional theory calculations, and pair distribution function analysis. The study reveals a peculiar ligand redistribution mechanism and improves the yield and control over nanocrystal size by modifying the synthesis method.
Article
Chemistry, Physical
Einar Sagstuen, Veronika Kugler, Eli Olaug Hole, Anders Lund
Summary: This study investigates the disadvantages of using the amino acid ala for solid state radiation dosimetry and explores the potential of other compounds. The compounds ammonium tartrate and lithium formate were found to have higher sensitivity to radiation exposure. The study also reveals differences in the molecular structures of the dominant room temperature radical compared to previous theories.
RADIATION PHYSICS AND CHEMISTRY
(2022)
Article
Chemistry, Analytical
Alexey A. Kagilev, Vladimir I. Morozov, Ekaterina M. Zueva, Zufar N. Gafurov, Ilya K. Mikhailov, Artyom O. Kantyukov, Il'yas F. Sakhapov, Nataliya A. Zhukova, Milyausha S. Kadyrova, Vakhid A. Mamedov, Dmitry G. Yakhvarov
Summary: The electrochemical properties of 2,2'-bibenzimidazole and its substituted analogues were investigated, revealing the formation of 2,2'-bibenzoimidazolylidene species for N-H derivatives via ECEC reaction mechanism, and the formation of radical anion and dianion species for N,N-dimethyl substituted derivative.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2022)
Article
Chemistry, Physical
Jens Arne Pedersen, Jens Spanget-Larsen
Summary: This study conducted measurements and analyses of the EPR spectrum of the gallate semiquinone radical tri-anion derived from gallic acid, resulting in the determination of splittings from 13C nuclei. The assignment of 13C HFS constants was supported by theoretical calculations and quantum chemical procedures, providing valuable insights into the electron spin structure of the radical.
JOURNAL OF MOLECULAR STRUCTURE
(2021)
Article
Chemistry, Multidisciplinary
Abhay K. Patel, Rajendra N. Jadeja, Neetu Patel, Ram N. Patel, Satish K. Patel, Ray J. Butcher, Santosh Kumar, Gaurav Kumar
Summary: Three new copper(II) complexes were synthesized and characterized in this study. The complexes exhibited characteristic absorption bands in the UV region and showed supramolecular structures formed by various non-covalent interactions. DFT calculations confirmed the experimental results. The complexes also showed good antioxidant and antibacterial properties.
RESULTS IN CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Abhay K. Patel, Rajendra N. Jadeja, Ray J. Butcher
Summary: The reaction of (Z)-2-(phenyl(2-(pyridin-2-yl)hydrazono)methyl)pyridine with copper(II) salt in methanol yields a series of five pentacoordinated mononuclear complexes. These complexes exhibit good SOD activity and paramagnetic behaviors. The structures and electrochemical properties of the complexes were investigated using DFT calculations, EPR spectral measurements, and Voltammetry techniques.
JOURNAL OF THE INDIAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Tilak Das, Giovanni Di Liberto, Gianfranco Pacchioni
Summary: The description of the band gap of halide perovskites at the level of density functional theory (DFT) still presents significant problems and deviations from experimental values. This work presents a pragmatic recipe to compute the band gap of halide perovskites with a minimum average error, and suggests a reliable computational strategy to screen new halide perovskite materials for solar energy conversion.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Ho Viet Thang, Thong Le Minh Pham, Gianfranco Pacchioni
Summary: The electronic properties of N-doped ZnO/Cu(111) bilayer films were studied using the DFT+U method, showing differences in oxidation state of N compared to free-standing ZnO bilayer films. The extra negative charge of N in N:ZnO/Cu(111) was attributed to electron transfer from the Cu support. This difference in oxidation state of the N dopant was demonstrated through analysis of Bader charge, magnetization, and density of states.
Article
Chemistry, Multidisciplinary
Juan J. Navarro, Mowpriya Das, Sergio Tosoni, Felix Landwehr, Maximilian Koy, Markus Heyde, Gianfranco Pacchioni, Frank Glorius, Beatriz Roldan Cuenya
Summary: N-Heterocyclic carbenes (NHCs) show superior properties in self-assembled monolayers (SAMs) and understanding the influence of the substrate on the molecular arrangement is crucial. This study reveals that on Cu(100), NHCs form mostly disordered phases, while on Cu(111), well-defined structures ranging from magic-number islands to molecular ribbons are observed. Diffusion and commensurability play a key role in determining the observed arrangements, providing insights into molecule-substrate interaction and the potential for tuning nanopatterned structures based on NHC assemblies.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Biochemistry & Molecular Biology
Ivana Miletto, Chiara Gionco, Maria Cristina Paganini, Erik Cerrato, Leonardo Marchese, Enrica Gianotti
Summary: This study presents the preparation and modification of upconversion nanoparticles with red upconversion emission for potential biological applications. The nanoparticles were functionalized with a silica shell to anchor an FDA approved photosensitizer, allowing the activation of photodynamic therapy in deep tissues using upconversion.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Chemistry, Physical
Juan J. Navarro, Mowpriya Das, Sergio Tosoni, Felix Landwehr, Markus Heyde, Gianfranco Pacchioni, Frank Glorius, Beatriz Roldan Cuenya
Summary: This study investigates the thermal reduction of copper oxide overlayers on Cu(111) in the presence of N-heterocyclic carbene (NHC) ligands using scanning tunneling microscopy and density functional theory. The researchers find that NHC ligands actively participate in the reduction of copper oxide and promote its removal at relatively low temperatures. Scanning tunneling spectroscopy is used to chemically identify metallic and oxide areas at the nanometric scale.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Multidisciplinary Sciences
Ilaria Barlocco, Luis A. Cipriano, Giovanni Di Liberto, Gianfranco Pacchioni
Summary: This study investigates the impact of different exchange-correlation functionals on the catalytic activity of single atom catalysts in hydrogen and oxygen evolution reactions. The results show that the choice of functional can lead to significant deviations in the predicted activity for different transition metals.
ADVANCED THEORY AND SIMULATIONS
(2023)
Article
Chemistry, Physical
Giovanni Di Liberto, Sergio Tosoni
Summary: We investigated the interface between carbon nitride (C3N4) and phosphorene nanosheets (P-ene) using Density Functional Theory (DFT) calculations. The formation of the interface is driven by Van der Waals forces. The thickness of P-ene nanosheets determines the band edges offsets and the separation of charge carriers. The system transitions from a nearly type-II to a type-I junction as the thickness of P-ene increases.
Review
Chemistry, Physical
Sergio Tosoni, Giovanni Di Liberto, Ivana Matanovic, Gianfranco Pacchioni
Summary: In this tutorial review, the state-of-the-art modeling approaches of Single Atom Catalysts (SAC) for water splitting and fuel cells reactions are reported. The discussion focuses on Hydrogen Evolution Reaction (HER), Oxygen Reduction Reaction (OER), Hydrogen Oxidation Reaction (HOR), and Oxygen Reduction Reaction (ORR). The aim is to emphasize the relevant aspects of SACs modeling and provide guidance for computational chemists and experimentalists. The review covers methodologies, prediction of electronic properties, validation of structural models, prediction of catalytic activity and selectivity, and analysis of current challenges and limitations.
JOURNAL OF POWER SOURCES
(2023)
Article
Nanoscience & Nanotechnology
Farahnaz Maleki, Giovanni Di Liberto, Gianfranco Pacchioni
Summary: In this work, the pH- and facet-dependent surface chemistry of TiO2/water interfaces was studied using ab initio molecular dynamics simulations. Acid-base equilibrium constants were determined at the interface, allowing for estimation of the pH at the point of zero charge, an important experimental observable. The amount of H+, OH-, and adsorbed H2O species on the surfaces was predicted based on simulated equilibrium constants, providing insights into water splitting semi-reactions. The complex morphology of TiO2 particles was approximated by considering different surfaces.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Physical
Sergio Tosoni
Summary: Mn3O4 Hausmannite thin films supported on (Cu, Ag, Au) coinage metals were investigated using DFT calculations. The interface between the films and metal support exhibited different lattice and ionic match, leading to different interactions. The films on Cu (111) and Au (111) weakly adhered due to unfavorable structural match, while strong adhesion was observed on Ag(100) with commensurate lattice and epitaxial growth. A negative charge flow from the support to the film was reported, resulting in the reduction of the film and an increase in magnetic moments of metal ions in the octahedral sublattice. The ferrimagnetic ordering varied in supported films exposing different crystal faces.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Alexander Fuhrich, Joachim Paier, Sergio Tosoni, Adrian Leandro Lewandowski, Leonard Gura, Wolf-Dieter Schneider, Gianfranco Pacchioni, Hans-Joachim Freund
Summary: Two-dimensional oxide films, including silica, germania, and mixed silica-germania films, supported on a Ru(0001) single crystal surface were studied. The modification of the properties of silica films through the incorporation of germanium atoms was investigated. X-ray photoelectron spectroscopy in combination with LEED and I/V LEEM measurements were used to judge the formation of mixed films.
ISRAEL JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Physical
Tilak Das, Sergio Tosoni
Summary: A self-consistent Hubbard-U search was conducted on the bulk honeycomb layered oxide SrRu2O6 for potential applications as Li and post-Li battery cathode materials. The study employed first-principles density functional theory (DFT) based calculations and analysis. The results revealed that intercalation of Li, Ca, and Al metals did not affect the SRO magnetic ordering. The host SRO showed a quenched magnetic moment after intercalation, indicating the transfer of electrons to neighboring Ru sublattices.
SOLID STATE IONICS
(2023)
Review
Chemistry, Physical
Giovanni Di Liberto, Ilaria Barlocco, Livia Giordano, Sergio Tosoni, Gianfranco Pacchioni
Summary: This article discusses several fundamental elements required for successful computational modeling of single-atom catalysts (SACs) for electrocatalytic applications, including the role of the adopted exchange-correlation functional within a given DFT approach and the role of the local coordination of the active transition metal atom. Next, it explores new intermediates that can form on SACs, which are not present on extended metal electrodes, and how to model solvation, with a focus on the dual role of water as both a solvent and a ligand on SACs. Finally, challenges related to the inclusion of pH and voltage in models and some open issues concerning the rational design of new SACs are discussed.
CURRENT OPINION IN ELECTROCHEMISTRY
(2023)
Article
Crystallography
Erik Cerrato, Chiara Gionco, Giuseppe Rizzelli Martella, Cecilia Clivati, Roberto Gaudino, Davide Calonico
Summary: Time and frequency metrology is crucial for forefront science and innovation. Currently, atomic frequency standards rely on atoms in vapor phase or trapped in magneto-optical lattices. Finding a solid-state material with suitable atoms as frequency references would simplify the setup of these standards. In this study, Er-doped LiYF4 was investigated as a potential benchmark material. The influence of Er concentration and isotope purity on transition linewidth was studied using high-resolution optical spectroscopy. The results suggest that this material is an interesting candidate for solid-state frequency references, with transition linewidths as low as 250 MHz at around 1530 nm.
Article
Chemistry, Physical
Ilaria Barlocco, Giovanni Di Liberto, Gianfranco Pacchioni
Summary: Single Atom Catalysts (SACs) bridge the gap between homogenous and heterogenous catalysis and show promise in various chemical reactions, including water splitting. This study focuses on SACs embedded in Covalent Organic Frameworks (COFs) and investigates their reactivity in Hydrogen and Oxygen Evolution Reactions (HER and OER, respectively) using density functional theory (DFT). The results reveal the formation of unique intermediates and shed light on the reaction mechanism, providing valuable insights for the design of novel catalytic materials.