Pub Date : 2024-11-30DOI: 10.1016/j.chemphys.2024.112546
Yuxiu Wang , Yuxuan Zhan , Zhong Xie , Cuicui Sun , Chunhua Yang
The adsorptions of H2S and HF molecules on N-confused porphyrin-like graphene composites G-CoNxC4-x (x = 2, 3, and 4) are investigated by first-principles calculations. Herein, the effective physisorption between G-CoNxC4-x substrates and H2S/HF toxic gases is revealed by no significant charge transfer and large adsorption spacing. Meanwhile, the exothermic adsorption effect and the thermodynamic stability of G-CoNxC4-x substrate are explained by the negative adsorption energies and ab initio molecular dynamics, respectively. Evidently, the G-CoN4 shows a remarkable enhancement in the HF sensing performance while G-CoN3C1 and G-CoN2C2 systems act as sharp responsive adsorbing H2S samples, which is confirmed by the demonstrable changes in electronic and magnetic properties, as well as reasonable short recovery time. Our comprehensive work suggests that fabricating N-confounding is an effective strategy for engineering porphyrin-like graphene-based gas sensitivity features and developing on-demand sensor.
{"title":"Investigation of gas-sensitive properties of N-confused porphyrin-like graphene composites: A viewpoint of first principle","authors":"Yuxiu Wang , Yuxuan Zhan , Zhong Xie , Cuicui Sun , Chunhua Yang","doi":"10.1016/j.chemphys.2024.112546","DOIUrl":"10.1016/j.chemphys.2024.112546","url":null,"abstract":"<div><div>The adsorptions of H<sub>2</sub>S and HF molecules on <em>N</em>-confused porphyrin-like graphene composites G-CoN<sub>x</sub>C<sub>4-x</sub> (x = 2, 3, and 4) are investigated by first-principles calculations. Herein, the effective physisorption between G-CoN<sub>x</sub>C<sub>4-x</sub> substrates and H<sub>2</sub>S/HF toxic gases is revealed by no significant charge transfer and large adsorption spacing. Meanwhile, the exothermic adsorption effect and the thermodynamic stability of G-CoN<sub>x</sub>C<sub>4-x</sub> substrate are explained by the negative adsorption energies and ab initio molecular dynamics, respectively. Evidently, the G-CoN<sub>4</sub> shows a remarkable enhancement in the HF sensing performance while G-CoN<sub>3</sub>C<sub>1</sub> and G-CoN<sub>2</sub>C<sub>2</sub> systems act as sharp responsive adsorbing H<sub>2</sub>S samples, which is confirmed by the demonstrable changes in electronic and magnetic properties, as well as reasonable short recovery time. Our comprehensive work suggests that fabricating <em>N</em>-confounding is an effective strategy for engineering porphyrin-like graphene-based gas sensitivity features and developing on-demand sensor.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"591 ","pages":"Article 112546"},"PeriodicalIF":2.0,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164757","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}
In this study, spin-polarized density functional theory (DFT) calculations were utilized to explore the oxygen reduction reaction (ORR) on a transition metal anchored to divacancy graphene (TM@dv-graphene). Our findings demonstrate that divacancy graphene serves as an effective substrate for stabilizing single transition metals, thereby facilitating the ORR. We elucidate the mechanisms of ORR by examining the adsorption of O2, OOH, OH, 2OH, and O intermediates, and identifying two competing ORR pathways: the O* and 2OH* mechanisms. Most TM@dv-graphene catalysts predominantly favor the O* mechanism, with Rh and Ir being notable exceptions that preferentially follow the 2OH* mechanism. Moreover, catalysts co-coordinated with B and N atoms significantly enhance the adsorption of key intermediates, thereby improving ORR activity Specifically, the Co-N4, Co-N2B2, Pd-N2B2, and Pt-N2B2 catalysts demonstrate promising ORR activity with lower overpotentials of 0.47, 0.46, 0.58, and 0.46 V, respectively. This work establishes a foundational framework for comprehending the electrochemical mechanisms of ORR, thus facilitating the design of highly efficient single-atom electrocatalysts.
{"title":"Nitrogen and boron coordinating atoms adjust single-atom catalyst anchored on divacancy defect graphene for highly efficient electrochemical oxygen reduction","authors":"Hsin-Tsung Chen , Yu-Ting Chiou , Tzu-Hui Chen , Hui-Lung Chen","doi":"10.1016/j.chemphys.2024.112540","DOIUrl":"10.1016/j.chemphys.2024.112540","url":null,"abstract":"<div><div>In this study, spin-polarized density functional theory (DFT) calculations were utilized to explore the oxygen reduction reaction (ORR) on a transition metal anchored to divacancy graphene (TM@dv-graphene). Our findings demonstrate that divacancy graphene serves as an effective substrate for stabilizing single transition metals, thereby facilitating the ORR. We elucidate the mechanisms of ORR by examining the adsorption of O<sub>2</sub>, OOH, OH, 2OH, and O intermediates, and identifying two competing ORR pathways: the O* and 2OH* mechanisms. Most TM@dv-graphene catalysts predominantly favor the O* mechanism, with Rh and Ir being notable exceptions that preferentially follow the 2OH* mechanism. Moreover, catalysts co-coordinated with B and N atoms significantly enhance the adsorption of key intermediates, thereby improving ORR activity Specifically, the Co-N<sub>4</sub>, Co-N<sub>2</sub>B<sub>2</sub>, Pd-N<sub>2</sub>B<sub>2</sub>, and Pt-N<sub>2</sub>B<sub>2</sub> catalysts demonstrate promising ORR activity with lower overpotentials of 0.47, 0.46, 0.58, and 0.46 V, respectively. This work establishes a foundational framework for comprehending the electrochemical mechanisms of ORR, thus facilitating the design of highly efficient single-atom electrocatalysts.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"591 ","pages":"Article 112540"},"PeriodicalIF":2.0,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164118","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}
Glass formation is commonly found in many different kinds of materials and systems. The conventional dynamic and thermodynamic properties considered are usually associated with the structural relaxation and the transport coefficient such as viscosity. Our studies of widely different classes of glass-forming materials over several decades have led to the discovery of processes faster than the structural relaxation are strongly connected to and inseparable from the structural relaxation in dynamic and thermodynamic properties. These faster processes include the caged molecular dynamics, and a special kind of secondary relaxation with the primitive relaxation of the Coupling Model as its precursor. Overwhelming evidences from experiments and simulations supporting this universal finding can be found in the review entitled “Universal Properties of Relaxation and Diffusion in Complex Materials: Originating from Fundamental Physics with Rich Applications“, published in Prog. Mater. Sci. 2023, 139, 101130. Consequently any theory of glass transition is neither complete nor fundamental if these important faster processes have not been considered. In this paper we examine the dynamics and thermodynamic properties of dry, hydrated, and solvated proteins and biomolecules to find the presence of the faster processes and verify their strong connections to the structural relaxation. Thus the dynamics and thermodynamics of the processes in the biomolecular systems considered are isomorphic to those in ordinary glass-forming material.
{"title":"The isomorphic dynamic properties of biomolecular matters and glass-forming materials","authors":"Simone Capaccioli , K.L. Ngai , Alessandro Paciaroni","doi":"10.1016/j.chemphys.2024.112543","DOIUrl":"10.1016/j.chemphys.2024.112543","url":null,"abstract":"<div><div>Glass formation is commonly found in many different kinds of materials and systems. The conventional dynamic and thermodynamic properties considered are usually associated with the structural relaxation and the transport coefficient such as viscosity. Our studies of widely different classes of glass-forming materials over several decades have led to the discovery of processes faster than the structural relaxation are strongly connected to and inseparable from the structural relaxation in dynamic and thermodynamic properties. These faster processes include the caged molecular dynamics, and a special kind of secondary relaxation with the primitive relaxation of the Coupling Model as its precursor. Overwhelming evidences from experiments and simulations supporting this universal finding can be found in the review entitled “Universal Properties of Relaxation and Diffusion in Complex Materials: Originating from Fundamental Physics with Rich Applications“, published in <em>Prog. Mater. Sci</em>. 2023, 139, 101130. Consequently any theory of glass transition is neither complete nor fundamental if these important faster processes have not been considered. In this paper we examine the dynamics and thermodynamic properties of dry, hydrated, and solvated proteins and biomolecules to find the presence of the faster processes and verify their strong connections to the structural relaxation. Thus the dynamics and thermodynamics of the processes in the biomolecular systems considered are isomorphic to those in ordinary glass-forming material.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"591 ","pages":"Article 112543"},"PeriodicalIF":2.0,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164754","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}
Pub Date : 2024-11-28DOI: 10.1016/j.chemphys.2024.112542
M.M. Mourad , T. Sharshar , M. Ghali , Y. Abdou , F. Elhussiny , O.M. Hemeda , H.M. Badran
This study probes the shielding efficacy of nano-PbO, examining the effects of milling on its microstructure and the consequences on X- and gamma-ray absorption. Characterization techniques, including XRD, Raman spectroscopy, TEM, and positron annihilation spectroscopy of commercial (milled for 10, 20, and 40 h) samples, as well as the synthesized PbO, reveal that milling induces a partial phase transformation from orthorhombic to tetragonal, alters particle morphology, and increases pore volume. Notably, milling does not significantly affect X-ray attenuation. The growing particle size with lower surface area, reduction of vacancy-type defects, and expanded pore size resulting from ball milling negatively influenced the probability of interaction of gamma-rays (<250 keV). Principal component analysis highlights the interplay between particle size, surface area, defect density, and pore size in determining shielding efficacy. This investigation underscores the importance of considering multiple parameters, beyond particle size, to optimize the radiation shielding performance of any material.
{"title":"Effect of mechanical ball milling on the microstructure and radiation shielding performance of nano-PbO","authors":"M.M. Mourad , T. Sharshar , M. Ghali , Y. Abdou , F. Elhussiny , O.M. Hemeda , H.M. Badran","doi":"10.1016/j.chemphys.2024.112542","DOIUrl":"10.1016/j.chemphys.2024.112542","url":null,"abstract":"<div><div>This study probes the shielding efficacy of nano-PbO, examining the effects of milling on its microstructure and the consequences on X- and gamma-ray absorption. Characterization techniques, including XRD, Raman spectroscopy, TEM, and positron annihilation spectroscopy of commercial (milled for 10, 20, and 40 h) samples, as well as the synthesized PbO, reveal that milling induces a partial phase transformation from orthorhombic to tetragonal, alters particle morphology, and increases pore volume. Notably, milling does not significantly affect X-ray attenuation. The growing particle size with lower surface area, reduction of vacancy-type defects, and expanded pore size resulting from ball milling negatively influenced the probability of interaction of gamma-rays (<250 keV). Principal component analysis highlights the interplay between particle size, surface area, defect density, and pore size in determining shielding efficacy. This investigation underscores the importance of considering multiple parameters, beyond particle size, to optimize the radiation shielding performance of any material.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"591 ","pages":"Article 112542"},"PeriodicalIF":2.0,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757499","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}
Pub Date : 2024-11-28DOI: 10.1016/j.chemphys.2024.112535
Francisco M. Fernández
In this Comment we point out two incorrect results in a paper published recently in this journal. In the first place, the fact that the maximum number of vibrational energy levels is not a variable parameter of the model because it is determined by the potential-energy function and, in particular, by the dissociation energy. In the second place, we argue that the vibrational thermodynamic functions for an excited electronic state of a diatomic molecule are of no physical utility because any physical application requires the more relevant contribution of the lower electronic states to the canonical partition function. To illustrate this point we show the calculation of the equilibrium constant for the dimerization of sodium using only spectroscopic information about the ground electronic state. The theoretical expression agrees remarkably well with the available experimental data.
{"title":"Comment on “Relativistic spinless energies and thermodynamic properties of sodium dimer molecule”","authors":"Francisco M. Fernández","doi":"10.1016/j.chemphys.2024.112535","DOIUrl":"10.1016/j.chemphys.2024.112535","url":null,"abstract":"<div><div>In this Comment we point out two incorrect results in a paper published recently in this journal. In the first place, the fact that the maximum number of vibrational energy levels is not a variable parameter of the model because it is determined by the potential-energy function and, in particular, by the dissociation energy. In the second place, we argue that the vibrational thermodynamic functions for an excited electronic state of a diatomic molecule are of no physical utility because any physical application requires the more relevant contribution of the lower electronic states to the canonical partition function. To illustrate this point we show the calculation of the equilibrium constant for the dimerization of sodium using only spectroscopic information about the ground electronic state. The theoretical expression agrees remarkably well with the available experimental data.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"591 ","pages":"Article 112535"},"PeriodicalIF":2.0,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757500","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}
Pub Date : 2024-11-28DOI: 10.1016/j.chemphys.2024.112541
Juan Yu , Xiaolin Zhang , Xinxin Liu , Xinglong Xu , Xingyu Chen , Haiyang He , Yue Zhang , Rong Peng , Peilun Shen , Dianwen Liu
This research investigates the utilization of Scutellaria Baicalensis Extract (SBE) as a depressant in the flotation separation of sphalerite and chalcopyrite with Potassium Amylxanthate (PAX) serving as the flotation collector. The feasibility of SBE as a sphalerite depressant at near neutral pH conditions was evaluated through flotation tests, and its depression mechanism was explored using contact angle measurements, zeta potential measurements, adsorption measurements and XPS analyses. Micro-flotation experiments demonstrated the efficacy of SBE as a sphalerite depressant. In artificial mixed mineral experiments, a Cu concentrate with a recovery of 92.55 % and a grade of 28.45 % Cu, and a Zn concentrate with a recovery of 94.43 % and a grade of 57.30 % Zn were obtained at an SBE concentration of 37.5 mg/L. Contact angle, zeta potential and adsorption measurements revealed that SBE was adsorbed onto both sphalerite and chalcopyrite surface, with stronger adsorption on sphalerite. The amount of SBE adsorption on sphalerite exceeded that on chalcopyrite, and SBE prevented the collector’s adsorption on sphalerite while minimally affecting chalcopyrite. XPS analysis results suggested that SBE likely acts through physical adsorption on the mineral surface.
{"title":"A novel eco-friendly depressant Scutellaria Baicalensis Extract SBE and its performance on flotation separation of chalcopyrite from sphalerite: A combined experimental and mechanism investigation","authors":"Juan Yu , Xiaolin Zhang , Xinxin Liu , Xinglong Xu , Xingyu Chen , Haiyang He , Yue Zhang , Rong Peng , Peilun Shen , Dianwen Liu","doi":"10.1016/j.chemphys.2024.112541","DOIUrl":"10.1016/j.chemphys.2024.112541","url":null,"abstract":"<div><div>This research investigates the utilization of Scutellaria Baicalensis Extract (SBE) as a depressant in the flotation separation of sphalerite and chalcopyrite with Potassium Amylxanthate (PAX) serving as the flotation collector. The feasibility of SBE as a sphalerite depressant at near neutral pH conditions was evaluated through flotation tests, and its depression mechanism was explored using contact angle measurements, zeta potential measurements, adsorption measurements and XPS analyses. Micro-flotation experiments demonstrated the efficacy of SBE as a sphalerite depressant. In artificial mixed mineral experiments, a Cu concentrate with a recovery of 92.55 % and a grade of 28.45 % Cu, and a Zn concentrate with a recovery of 94.43 % and a grade of 57.30 % Zn were obtained at an SBE concentration of 37.5 mg/L. Contact angle, zeta potential and adsorption measurements revealed that SBE was adsorbed onto both sphalerite and chalcopyrite surface, with stronger adsorption on sphalerite. The amount of SBE adsorption on sphalerite exceeded that on chalcopyrite, and SBE prevented the collector’s adsorption on sphalerite while minimally affecting chalcopyrite. XPS analysis results suggested that SBE likely acts through physical adsorption on the mineral surface.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"591 ","pages":"Article 112541"},"PeriodicalIF":2.0,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748617","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}
Pub Date : 2024-11-28DOI: 10.1016/j.chemphys.2024.112544
Jamilah A Asiri , Walid M.I. Hasan , Abdesselem Jedidi , Shaaban A. Elroby , Saadullah G. Aziz , Osman I. Osman
Theoretical calculations suggest possible designs of Thermally Activated Delayed Fluorescence (TADF) emitters using three-coordinate aluminium (Al-X3) complexes for the design of organometal light emitting diodes. We investigate the optical properties of gas-phase and toluene-solvated Ac-Al, Ac-Al-F, Ac-Al-CN and Ac-Al-NO2 complexes using DFT/TDA methods. All calculations were carried out using the long-range corrected ωB97XD functional with optimal ω values. Except for Ac-Al-CN contender, the aluminum atom has magnified the spin–orbit couplings between the excited singlet (S1) and triplet (T1) states. The decrease in the reorganization energies of Ac-Al-CN and Ac-Al-NO2 complexes has maximized their reverse intersystem crossing rate constants. The presence of the strong electron withdrawing nitro group has further stabilized its LUMO together with improving both its oscillator strength and the emission decay rate constant. This contender is predicted to be the most prominent TADF emitter and highly promising for designing diode devises amongst the understudy complexes.
{"title":"Could organoaluminium complexes act as prominent TADF emitters for designing efficient diode devices? A DFT/TDA simulation study","authors":"Jamilah A Asiri , Walid M.I. Hasan , Abdesselem Jedidi , Shaaban A. Elroby , Saadullah G. Aziz , Osman I. Osman","doi":"10.1016/j.chemphys.2024.112544","DOIUrl":"10.1016/j.chemphys.2024.112544","url":null,"abstract":"<div><div>Theoretical calculations suggest possible designs of Thermally Activated Delayed Fluorescence (TADF) emitters using three-coordinate aluminium (Al-X<sub>3</sub>) complexes for the design of organometal light emitting diodes. We investigate the optical properties of gas-phase and toluene-solvated Ac-Al, Ac-Al-F, Ac-Al-CN and Ac-Al-NO<sub>2</sub> complexes using DFT/TDA methods. All calculations were carried out using the long-range corrected ωB97XD functional with optimal ω values. Except for Ac-Al-CN contender, the aluminum atom has magnified the spin–orbit couplings between the excited singlet (S<sub>1</sub>) and triplet (T<sub>1</sub>) states. The decrease in the reorganization energies of Ac-Al-CN and Ac-Al-NO<sub>2</sub> complexes has maximized their reverse intersystem crossing rate constants. The presence of the strong electron withdrawing nitro group has further stabilized its LUMO together with improving both its oscillator strength and the emission decay rate constant. This contender is predicted to be the most prominent TADF emitter and highly promising for designing diode devises amongst the understudy complexes.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"591 ","pages":"Article 112544"},"PeriodicalIF":2.0,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164752","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}
Pub Date : 2024-11-27DOI: 10.1016/j.chemphys.2024.112545
Qingqing Zhang , Shun Li , Saifei Yuan , Xiaole Qiu , Chuan-Lu Yang
The effects of atomic electronegativity (O, S and Se) on the excited state intramolecular proton transfer (ESIPT) behavior of fluorescent benzazolyl-4-quinolones derivatives have been investigated theoretically. Analysis of structure parameters and infrared vibrational spectra indicate that the intramolecular hydrogen bonds (O1H1⋯N1) are gradually strengthened in the first (S1) excited state as the atomic electronegativity diminishes (O → S → Se). The topological parameters, reduced density gradient (RDG) scatter plots and interaction region indicator (IRI) isosurface further confirm our results. The energy gap of molecular orbitals reflect that the less atomic electronegativity prompt greater excited state reactivity. In addition, the constructed potential energy curves (PECs) reveal that Se substituent has lower potential barrier (0.42 kcal/mol), which is more likely to accelerate the occurrence of ESIPT process. These results show that the atomic electronegativity helps to regulate the ESIPT process, which will pave the way for the design and synthesis of ESIPT-based fluorophores in future.
{"title":"Tactfully regulating the ESIPT mechanism of novel benzazolyl-4-quinolones fluorophore by atomic electronegativity","authors":"Qingqing Zhang , Shun Li , Saifei Yuan , Xiaole Qiu , Chuan-Lu Yang","doi":"10.1016/j.chemphys.2024.112545","DOIUrl":"10.1016/j.chemphys.2024.112545","url":null,"abstract":"<div><div>The effects of atomic electronegativity (O, S and Se) on the excited state intramolecular proton transfer (ESIPT) behavior of fluorescent benzazolyl-4-quinolones derivatives have been investigated theoretically. Analysis of structure parameters and infrared vibrational spectra indicate that the intramolecular hydrogen bonds (O<sub>1</sub><img>H<sub>1</sub>⋯N<sub>1</sub>) are gradually strengthened in the first (S<sub>1</sub>) excited state as the atomic electronegativity diminishes (O → S → Se). The topological parameters, reduced density gradient (RDG) scatter plots and interaction region indicator (IRI) isosurface further confirm our results. The energy gap of molecular orbitals reflect that the less atomic electronegativity prompt greater excited state reactivity. In addition, the constructed potential energy curves (PECs) reveal that Se substituent has lower potential barrier (0.42 kcal/mol), which is more likely to accelerate the occurrence of ESIPT process. These results show that the atomic electronegativity helps to regulate the ESIPT process, which will pave the way for the design and synthesis of ESIPT-based fluorophores in future.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"590 ","pages":"Article 112545"},"PeriodicalIF":2.0,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142744525","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}
Pub Date : 2024-11-26DOI: 10.1016/j.chemphys.2024.112536
Tabouli Eric Da-yang , Jean Jules Fifen , Jeanet Conradie
In the present work, we investigated the potential energy surfaces (PESs) of the structures of the ion in methanol clusters in two different media: gas and solvent phases. The effects of medium polarization by the integral equation formalism polarized continuum model (IEF-PCM) on structural and energetic parameters were examined on the conformers of the clusters using the M06-2X/6-31++G(d,p) level of theory. Thus, in the solvent phase, the cluster structures are hexa-coordinated in the global minimum isomer. The study of the temperature dependency shows that the hexa-, and penta-coordinated structures compete with a large predominance of the hexa-coordinate structures with two solvation shells in the solvent phase. The Wiberg bond indices (WBI) analysis of the ionic bond confirms the structural study. In the IEF-PCM solvent compared to the gas medium, Wiberg bond indices of the tetra-, and penta-coordinate conformers are weaker, and the hexa-coordinate conformers in both media are nearly identical. This proves that compared to the solvent phase, the dative bond is stronger in the gas phase. This is supported by the significant difference in the electronic binding energies at saturation found with a single fitting function which are -88.6 and -146.6 in the solvent and gas phases, respectively.
{"title":"Exploration of the potential energy surfaces of the Cu2+(MeOH)n=9,10 clusters: Solvent phase vs gas phase","authors":"Tabouli Eric Da-yang , Jean Jules Fifen , Jeanet Conradie","doi":"10.1016/j.chemphys.2024.112536","DOIUrl":"10.1016/j.chemphys.2024.112536","url":null,"abstract":"<div><div>In the present work, we investigated the potential energy surfaces (PESs) of the structures of the <span><math><msup><mrow><mi>Cu</mi></mrow><mrow><mn>2</mn><mo>+</mo></mrow></msup></math></span> ion in methanol clusters in two different media: gas and solvent phases. The effects of medium polarization by the integral equation formalism polarized continuum model (IEF-PCM) on structural and energetic parameters were examined on the conformers of the <span><math><mrow><msup><mrow><mi>Cu</mi></mrow><mrow><mn>2</mn><mo>+</mo></mrow></msup><msub><mrow><mrow><mo>(</mo><mi>MeOH</mi><mo>)</mo></mrow></mrow><mrow><mi>n</mi><mo>=</mo><mn>9</mn><mo>,</mo><mn>10</mn></mrow></msub></mrow></math></span> clusters using the M06-2X/6-31++G(d,p) level of theory. Thus, in the solvent phase, the cluster structures are hexa-coordinated in the global minimum isomer. The study of the temperature dependency shows that the hexa-, and penta-coordinated structures compete with a large predominance of the hexa-coordinate structures with two solvation shells in the solvent phase. The Wiberg bond indices (WBI) analysis of the ionic bond confirms the structural study. In the IEF-PCM solvent compared to the gas medium, Wiberg bond indices of the tetra-, and penta-coordinate conformers are weaker, and the hexa-coordinate conformers in both media are nearly identical. This proves that compared to the solvent phase, the dative bond is stronger in the gas phase. This is supported by the significant difference in the electronic binding energies at saturation found with a single fitting function which are -88.6 and -146.6 <span><math><mrow><mtext>kJ</mtext><mspace></mspace><mtext>mol</mtext><msup><mrow></mrow><mrow><mi>−1</mi></mrow></msup></mrow></math></span> in the solvent and gas phases, respectively.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"590 ","pages":"Article 112536"},"PeriodicalIF":2.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142744524","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}
Pub Date : 2024-11-26DOI: 10.1016/j.chemphys.2024.112539
Maddina Dinesh kumar , D.Serafin Grace , P. Durgaprasad , José Luis Díaz Palencia
This work used ternary hybrid nanofluids containing motile gyrotactic microorganisms and irregularly shaped platelet, cylindrical, and spherical nanoparticles to evaluate heat transport in a stenosis artery with volume fractions of Cobalt , Silver , and Gold . The proper self-similarity variables are used to convert the fluid transport equations into ordinary differential equations., which the BVP4C then solves in MATLAB. We analyse the effects of various parameters, including curvature, magnetic intensity, thermal radiation, and non-Newtonian behaviour, regarding Nusselt numbers, temperature profiles, skin friction, and velocity distribution. The study reveals that higher curvature enhances convective heat transfer despite initial resistance due to flow constriction, while magnetic fields stabilise flow patterns and improve heat transfer via nanoparticle alignment. Thermal radiation amplifies heat transfer by reducing boundary layer thickness and enhancing energy absorption. The non-linear relationship between magnetic intensity, thermal radiation, and the Eckert number that our results reveal emphasizes the need for more vital magnetic fields to sustain stability and effective heat transfer as thermal radiation rises. This work offers valuable information for improving nanofluid, automotive, and biomedical engineering heat transfer mechanisms. It can improve heat therapy, targeted medication administration, and diagnostic imaging in biomedicine. It provides advancements in gasoline additives, lubricants, and engine cooling systems for the automotive industry. It can improve solar energy systems, microfluidics, and heat transfer systems in nanofluid engineering.
{"title":"Response surface optimisation on Non-Uniform shapes ternary hybrid nanofluid flow in stenosis artery with motile gyrotactic microorganisms","authors":"Maddina Dinesh kumar , D.Serafin Grace , P. Durgaprasad , José Luis Díaz Palencia","doi":"10.1016/j.chemphys.2024.112539","DOIUrl":"10.1016/j.chemphys.2024.112539","url":null,"abstract":"<div><div>This work used ternary hybrid nanofluids containing motile gyrotactic microorganisms and irregularly shaped platelet, cylindrical, and spherical nanoparticles to evaluate heat transport in a stenosis artery with volume fractions of Cobalt <span><math><mfenced><mrow><mrow><msub><mi>φ</mi><mn>1</mn></msub><mo>=</mo><mn>0.01</mn></mrow></mrow></mfenced></math></span>, Silver <span><math><mfenced><mrow><mrow><msub><mi>φ</mi><mn>2</mn></msub><mo>=</mo><mn>0.01</mn></mrow></mrow></mfenced></math></span>, and Gold <span><math><mfenced><mrow><mrow><msub><mi>φ</mi><mn>3</mn></msub><mo>=</mo><mn>0.01</mn></mrow></mrow></mfenced></math></span>. The proper self-similarity variables are used to convert the fluid transport equations into ordinary differential equations., which the BVP4C then solves in MATLAB. We analyse the effects of various parameters, including curvature, magnetic intensity, thermal radiation, and non-Newtonian behaviour, regarding Nusselt numbers, temperature profiles, skin friction, and velocity distribution. The study reveals that higher curvature enhances convective heat transfer despite initial resistance due to flow constriction, while magnetic fields stabilise flow patterns and improve heat transfer via nanoparticle alignment. Thermal radiation amplifies heat transfer by reducing boundary layer thickness and enhancing energy absorption. The non-linear relationship between magnetic intensity, thermal radiation, and the Eckert number that our results reveal emphasizes the need for more vital magnetic fields to sustain stability and effective heat transfer as thermal radiation rises. This work offers valuable information for improving nanofluid, automotive, and biomedical engineering heat transfer mechanisms. It can improve heat therapy, targeted medication administration, and diagnostic imaging in biomedicine. It provides advancements in gasoline additives, lubricants, and engine cooling systems for the automotive industry. It can improve solar energy systems, microfluidics, and heat transfer systems in nanofluid engineering.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"590 ","pages":"Article 112539"},"PeriodicalIF":2.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142744523","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}
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