Physical Chemistry Chemical Physics最新文献

{"title":"Negative thermal expansion and linear compressibility in 1H-imidazol-3-ium 2-hydroxybenzoate with a helical network of hydrogen bonds","authors":"Sylwia Zieba, Alina Teresa Dubis, Michalina Rusek, Andrzej Katrusiak, Andrzej K. Gzella, Andrzej Lapinski","doi":"10.1039/d4cp04519j","DOIUrl":"https://doi.org/10.1039/d4cp04519j","url":null,"abstract":"1H-imidazol-3-ium-2-hydroxybenzoate (imidazolium salicylate or SalImi) is an organic molecular crystal with helical hydrogen-bonded network. Crystallographic structure and quantum theory of atoms in molecule calculations are used to analyse the helical structure parameters. Negative area and negative linear temperature expansion range from 300 to 180 K and 180 to 100 K, respectively. Hydrogen bonding coupling below 180 K is associated with the temperature change in crystal behaviour. The crystal displays negative linear compressibility in the a-direction. The negative temperature expansion and negative linear compressibility are described by the \"helical\" mechanism. X-ray diffraction and vibrational spectroscopy were used for the structural and macroscopic analysis. The paper presents an analysis of the crystalline structure in the temperature range from 100 to 300 K and pressures from atmospheric to 2.27 GPa. In addition, the vibrational structure was analysed using Raman and infrared spectroscopy in the temperature range from 5 to 300 K and pressures from atmospheric to 3.56 GPa.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"18 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143713374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revisiting the Radical Trapping Activity of N-H and O-H in N-Phenylhydroxylamine: A DFT Study","authors":"Pham Thi Thu Thao, Dinh Quy Huong, Thong Nguyen Minh, Mai Van Bay, Son Tung Ngo, Quan Van Vo, Pham Cam Nam","doi":"10.1039/d5cp00641d","DOIUrl":"https://doi.org/10.1039/d5cp00641d","url":null,"abstract":"Hydroxylamines have been identified as promising antioxidants that can effectively scavenge free radicals primarily through a hydrogen transfer mechanism. Specifically, for N-phenylhydroxylamines, it is believed that both N-H and O-H bonds serve as two hydrogen- donating centers responsible for this task. M06-2X/6-311++G(d,p) and CBS-QB3 methods were used to re-evaluate the bond dissociation enthalpies of N-H and O-H and the results were found to be in agreement with each other. The revisited BDE(N-H) values in the gas phase, DMSO and water media are 74.8, 77.1, and 78.9 kcal/mol, respectively, while the BDE(O-H) values are about 5.0, 7.6, and 6.0 kcal/mol lower in comparison. Additionally, the effect of substitution with halogen, electron-donating, and electron- withdrawing groups at the para site of the aromatic ring of ArNHOH on the BDEs of both N-H and O-H bonds was evaluated. In addition to examining the role of O-H and N-H bonds in the trapping of radicals, the current study incorporated a kinetic aspect to insight the comprehension of the implicated mechanisms. Moreover, an evaluation of the N-phenylhydroxylamine's antioxidant capability was carried out through the execution of a DPPH assay.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"183 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143713260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring the origin of electron spin polarization in the metal-containing chromophore-radical system via multireference calculations","authors":"Ryosuke Sowa, Yuki Kurashige","doi":"10.1039/d4cp04695a","DOIUrl":"https://doi.org/10.1039/d4cp04695a","url":null,"abstract":"The electron spin polarization (ESP) phenomenon in photoexcited chromophore-radical connected systems was analyzed by multi-reference electronic structure calculations. We focused on the bpy-M-CAT-mPh-NN (bpy = 4,4-di-tert-butyl-2,2-bipyridine, M = Pt or Pd, CAT = 3-tert-butylcatecholate, mPh = meta-phenylene, NN = nitronyl nitroxide) reported by Kirk et al., which is a connected system consisting of a donor-acceptor complex and a radical, and elucidated the mechanism behind the reversal of the sign of photoinduced ESP depending on the metal species. The low-lying electronic states of these molecules were revealed through the multi-reference theory, suggesting that the ligand-to-ligand charge-transfer states play a significant role. Additionally, several structural factors that influence the energies of the excited states were identified. To enhance our understanding of the ESP, we incorporated spin-orbit coupling as a direct transition term between excited states and explicitly considered its effects on the ESP. The results of evaluating transition rates through a transition simulation indicate that when the influence of spin-orbit coupling is significant, the sign of the ESP in the ground state can reverse. This novel ESP mechanism mediated by spin-orbit coupling may offer fundamental insights for designing molecules to precisely control electron distribution across multiple spin states.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"61 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143713265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Dimerization Effects on Electronic Properties of OLED Candidate Materials for Optimized Performance: A Quantum DFT Study","authors":"Ramtin Khoshdel Rad, Mohammad Hossein Hoorzad, Mahdi Zarif","doi":"10.1039/d5cp00213c","DOIUrl":"https://doi.org/10.1039/d5cp00213c","url":null,"abstract":"In recent years, there has been a growing interest in organic light-emitting diode (OLED) materials, highlighting the importance of a thorough understanding of the key factors that influence their electronic and non-linear optical (NLO) properties. To achieve this objective, we considered five candidate OLED compounds: Dibenzothio-phen-sulfone-3-yl-9-phenyl-9H-carbazole (DBTS-CzP), 9H-thioxanthene-9-one-dibenzothiophene-sulfone (TXO-DBTS), spiro[fluorene-9,9-thioxanthene]-10,10-dioxide (SpDBTS), 9-[4-(Diphenylphosphoryl)-2,2-dimethyl-4-biphenylyl]-9H-carbazole (mCBPPO), and N,N-Bis[2-(pyridin-2-yl)phenyl]-N,N-di(n-butyl)phenylamine (DPA-2Py). We employed density functional theory (DFT) and time-dependent DFT (TD-DFT) methods to investigate how dimerization can affect their electronic and NLO characteristics. The results of electronic structure analyses, including HOMO-LUMO gaps and NLO characteristics, reveal that dimerization enhances dipole moments and polarizabilities, facilitating improved charge transfer and electronic transitions. Among the studied compounds, TXO-DBTS demonstrates stable electronic properties and exhibits enhanced NLO characteristics post-dimerization --such as efficient charge mobility and superior color purity-- positioning it as a promising candidate for advanced OLED applications. These findings underscore dimerized structures' potential to enhance optoelectronic device performance.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"33 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143723796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Theoretical Insights into Aggregation-Induced Emission of Bis(cyanostyryl)pyrrole Derivatives","authors":"C. Femina, Toshiya Yamagami, Norifumi Yamamoto, Reji Thomas, P. K. Sajith","doi":"10.1039/d4cp01291g","DOIUrl":"https://doi.org/10.1039/d4cp01291g","url":null,"abstract":"The molecular architecture and the positioning of the cyano group in cyanostilbene derivatives give rise to intriguing variations in their photophysical properties. The present study provides theoretical insights into the contrasting photoluminescence behaviors of bis(cyanostyryl)pyrrole derivatives with different cyano group positions. Using quantum mechanics/molecular mechanics (QM/MM) free energy perturbation methods, we investigated o-DCSP and i-DCSP isomers, which exhibited markedly different fluorescence quantum yields in the solution (Φ<small>_f</small> = 0.0036 vs. 0.43) and aggregated states (Φ<small>_f</small> = 0.15 vs. 0.12). We identified the minimum energy conical intersection (MECI) structures for both isomers, characterized by substantial rotation and pyramidalization of one ethylenic C=C bond, and determined the minimum energy path (MEP) connecting the Franck-Condon point to the MECI using the string method. By calculating the free energy profiles along this MEP, we revealed significant differences in energy barriers: o-DCSP showed a low barrier in solution (0.57 eV) that dramatically increased upon aggregation (2.36 eV), explaining its aggregation-induced emission behavior, whereas i-DCSP maintains relatively high barriers in both states (1.40 eV and 1.67 eV), resulting in efficient emission regardless of the environment. These findings establish a quantitative molecular-level understanding of the structure-property relationships in fluorescent materials and provide design principles for developing high-performance luminescent compounds with tailored emission characteristics for specific applications.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"5 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143713375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring room-temperature anti-ferromagnetism in newly predicted 2D MBene M4B6 (M: Cr, Mn, Fe) monolayer using first-principles calculations","authors":"Abdullah Abdullah, Altaf Ur Rahman, Milton Andre Tumelero, Liao Jujian, Sergio Magalhaes, Mohammed A. Amin, Guang-Hua Guo","doi":"10.1039/d5cp00416k","DOIUrl":"https://doi.org/10.1039/d5cp00416k","url":null,"abstract":"The search for two-dimensional (2D) materials is rapidly expanding. Here, we predict a new series of 2D MBene M$_4$B$_6$ monolayer composed of transition metal (M: Cr, Mn, Fe) and borron (B) atoms, thereby extending the family of MBene. A detailed first- principles calculations demonstrate that the new MBene materials have stable hexagonal crystal structures and antiferromagnetic ground state. The average magnetic moment per magnetic ion in antiferromagnetic state is calculated as 2.10 µB /atom, 2.60 µB /atom, and 1.38 µB /atom for Cr4B6 , Mn4B6 , and Fe4B6 monolayers, respectively. The calculated spin-polarized electronic band structures show the narrow gap semiconducting character in Cr and Mn-based MBene monolayers under consideration. Furthermore, the stability of magnetization against thermal fluctuations is confirmed by the energy barrier created by magnetocrystalline an-isotropy energy (MAE), which is as high as 0.822 meV/cell with respect to hard axes for Mn4 B6 monolayer. The high value of MAE indicated that the sin moments will be aligned out of the plane in a 2D Ising Model fashion. The Neel temperatures for Cr4B6 , Mn4B6 , and Fe4B6 MBene monolayers are estimated to be 302.09 K, 393.05 K, and 233.62 K, respectively, by using Monte Carlo (MC) simulations. These results indicate that the newly predicted 2D MBene M4B6 monolayers are promising materials for spintronic nanodevices at room temperature.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"57 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143713376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Resistivity mapping of SiC wafers by quantified Raman spectroscopy","authors":"Elisa Calà, Simone Cerruti, Cristina Sanna, Marco Maffè, Wen Chin Hsu, Man Hsuan Lin, Luciano Ramello, Giorgio Gatti","doi":"10.1039/d4cp04545a","DOIUrl":"https://doi.org/10.1039/d4cp04545a","url":null,"abstract":"μRaman spectroscopy measurements were used to study the resistivity in 4H-SiC samples by intercalibrating with Eddy current measurements (eddy-current probe that accurately measures bulk resistivity of wafers). The position and line width associated with the Raman longitudinal optical phonon-plasmon coupled (LOPC) mode were used since their variation from the reference values of a material in the absence of dopant-generated defects is proportional to the amount of the free carrier concentration in the conduction band present in the semiconductor. Using wafers of known resistivity to calibrate the model and deconvolving the individual recorded spectra, a multi-variable model was created to predict the resistivity of individual map points. Resistivity was thus predicted in a pointwise manner resulting in maps of 92 points over a 6-inch diameter area of a wafer, from which false-colour images were created showing the spatial distribution along the <em>X</em> and <em>Y</em> axes, and in the bulk, along the <em>Z</em> axis of the resistivity. The analysis procedure was automated by creating suitable R-language codes that extract the necessary information on the individual aspects of the analysis and create the images described above from a single dataset.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"125 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Graphene quantum dots reducing oxidation behavior and mechanical damage of epoxy resin irradiated by γ-rays","authors":"Shengkai Liu, Zhisong Li, Jinxia Hou, Peiwen Yang, Chunying Min, Siqi Liu, Xiaoyuan Pei, Ruiqi Shao, Amna Siddique, Zhiwei Xu","doi":"10.1039/d5cp00080g","DOIUrl":"https://doi.org/10.1039/d5cp00080g","url":null,"abstract":"Epoxy resin is a widely used polymer. However it will generate highly reactive free radicals when exposed to radiation, which impacts its physical and chemical structure. In this study, graphene quantum dots were integrated into the epoxy resin matrix as free radical scavengers to enhance its stability in irradiated environments. Notably the oxide layer of the epoxy resin measured approximately 480 μm in thickness, whereas that of the GQD/EP nanocomposites was significantly thinner, at about 180 μm. After irradiation, the mechanical properties of the epoxy resin decreased by 49%, and the glass transition temperature decreased by 4.4 °C. In contrast the mechanical properties of GQDs/EP nanocomposites decreased by 35%, and its glass transition temperature decreased by only 2.2 °C. These findings indicate that GQDs nanoparticles can effectively enhance the radiation resistance of epoxy resins. Furthermore, we explored the mechanism by which GQDs scavenge free radicals within the epoxy resin matrix.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"23 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tritium Adsorption and Absorption on (100) and (001) Surfaces of Pure and Tin Defective Zirconium","authors":"Morgan Redington, Hari Paudel, De Nyago Tafen, Daniel Patrick Miller, Eva Zurek, Yuhua Duan","doi":"10.1039/d5cp00215j","DOIUrl":"https://doi.org/10.1039/d5cp00215j","url":null,"abstract":"Zirconium alloys such as Zircaloy-4 are used as tritium (T) getter materials in tritium-producing burnable absorber rods (TPBARs) due to their ability to capture T, thereby forming metal hydrides. Developing an understanding of T adsorption onto Zircaloy prior to diffusion into the subsurface is relevant for rational tritium getter and TPBAR design, to improve material properties for nuclear applications. Herein, density functional theory calculations revealed the preferred binding sites for T adsorption on Zr(001) and Zr(100). The energy barriers of T transfer, along the surface and from the surface to the subsurface were computed. The adsorption properties of Zr(001) were found to be superior to those of Zr(100). Surface tin impurities were found to strongly repel T. The presence of subsurface and surface tin resulted in higher absorption energy barriers for both the forward and reverse processes. Based on the calculated energy barriers, a surface to surface T diffusion coefficient of 9.53 x 10<small>^-10</small> m<small>²</small>s<small>^-1</small> is expected for pristine Zr(001). A surface to subsurface T diffusion coefficient on the order of 10<small>^-13</small> m<small>²</small>s<small>^-1</small> is predicted in pristine Zr, decreasing to 10<small>^-19</small> m<small>²</small>s<small>^-1</small> for the transfer with a subsurface tin impurity.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"21 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"When Carbon Monoxide goes “Upside Down”: Vibrational Signatures of CO at NaCl(100) from Ab Initio Molecular Dynamics","authors":"Shreya Sinha, Alec M Wodtke, Peter Saalfrank","doi":"10.1039/d4cp04671d","DOIUrl":"https://doi.org/10.1039/d4cp04671d","url":null,"abstract":"CO adsorbed on NaCl(100) is a model system for surface science showing a rich variety of interesting phenomena. It features several adsorption phases like tilted / antiparallel or perpendicular / upright, very long vibrational lifetimes of the CO internal stretch (IS) mode, anharmonicity-driven vibrational energy pooling, “C-bound” vs. “O-bound” adsorption, and heavy-atom gateway tunneling during CO inversion at low temperatures. Typically, these features and phenomena are experimentally probed by stationary and time-resolved vibrational spectra, exhibiting characteristic differences between the various adsorption modes and phases. To gain atom- and time-resolved insight into vibrational response of CO molecules on NaCl(100), vibrational density of states (VDOS), Infrared (IR) and Vibrational Sum Frequency (VSF) spectra are computed from Velocity Velocity Correlation Functions (VVCFs) by Ab Initio Molecular Dynamics (AIMD) for various coverages, temperatures and phases. In agreement with experiments, we find that increasing CO (“C-bound”) coverages as well as CO inversion lead to redshifts of the CO IS mode. We predict more diffuse spectra at T = 300 K compared to 30 K, reflecting the disorder of adsorbates and monolayer instability at room temperature. Analyzing molecularly decomposed and internal VDOS curves as well as computed non-linear correlation matrices give further insight into the complex molecular dynamics underlying the vibrational spectra, notably for the low-frequency regime where frustrated rotations, translations and intermolecular mo- tions come into play. On a methodological side, we also test and discuss some intricate details of how to compute IR and VSF response using a modified formulation of the VVCF methods [Ohto et al., J. Chem. Phys., 2015, 143, 124702], by including time and angle-dependent dipole and polarizability derivatives as well as intermolecular couplings by cross correlations. Their effect on computed vibrational spectra is studied. These findings provide a detailed, microscopic insight into the picosecond vibrational spectra and dynamics of CO on NaCl(100), highlighting the effects of temperature, coverage, and changes in adsorbate orientation.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"61 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}