Density functional theory(DFT)calculations were employed to investigate the adsorption behavior of NH_(3),AsH_(3),PH_(3),CO_(2),and CH_(4)molecules on both pristine and mono-vacancy phosphorene sheets.The pristine pho...Density functional theory(DFT)calculations were employed to investigate the adsorption behavior of NH_(3),AsH_(3),PH_(3),CO_(2),and CH_(4)molecules on both pristine and mono-vacancy phosphorene sheets.The pristine phosphorene surface showsweak physisorption with all the gasmolecules,inducing onlyminor changes in its structural and electronic properties.However,the introduction ofmono-vacancies significantly enhances the interaction strength with NH_(3),PH_(3),CO_(2),and CH_(4).These variations are attributed to substantial charge redistribution and orbital hybridization in the presence of defects.The defective phosphorene sheet also exhibits enhanced adsorption energies,along with favorable sensitivity and recovery characteristics,highlighting its potential as a promising gas sensor for NH_(3),AsH_(3),PH_(3),CO_(2),and CH_(4)at ambient conditions.展开更多
Efficient surface passivation is critical for achieving high-performance perovskite solar cells(PSCs),yet the discovery of optimal passivators remains a time-consuming,trial-and-error process.Here,we report a synergis...Efficient surface passivation is critical for achieving high-performance perovskite solar cells(PSCs),yet the discovery of optimal passivators remains a time-consuming,trial-and-error process.Here,we report a synergistic machine learning(ML)and density functional theory(DFT)approach that enables predictive and rapid identification of effective passivation materials.By training an XGBoost model(91.3%accuracy)with DFT-derived molecular descriptors and activity calculations,we identify 2-(4-aminophenyl)-3H-benzimidazol-5-amine(APBIA)as a promising passivator.Experimental validation demonstrates that APBIA effectively removes surface impurities and passivates defects within perovskite films,leading to a significant increase in power conversion efficiency(PCE)from 22.48%to 25.55%(certified as 25.02%).This ML-DFT framework provides a generalizable pathway for accelerating the development of advanced functional materials for photovoltaic applications.展开更多
Cis-trans isomerization of [9]-annulenanion（1） and its 2-fluoro-,2-chloro-and 2-bromo-derivatives（2,3 and 4,respectively） were investigated at the HF/6-31G＊ and B3LYP/6-311＋＋G＊＊ levels of theory.Cis,cis,cis,c...Cis-trans isomerization of [9]-annulenanion（1） and its 2-fluoro-,2-chloro-and 2-bromo-derivatives（2,3 and 4,respectively） were investigated at the HF/6-31G＊ and B3LYP/6-311＋＋G＊＊ levels of theory.Cis,cis,cis,cis structures appear more stable than their corresponding cis,cis,cis,trans-isomers.The relative height of energy barriers for cis-trans isomerization is：2cis 〉1cis 〉3cis〉 4cis.This trend for the reverse trans-cis isomerization follows the electronegativity of the substituent at C-2（2trans 3trans 4trans 1trans）.展开更多
Various cyclic N_8 isomers are considered at the levels of B3 LYP/6-311++G(d,p) and B3 LYP/c PVTZ. Some energies and molecular orbital properties are obtained. The structures are found to be stable in the singlet stat...Various cyclic N_8 isomers are considered at the levels of B3 LYP/6-311++G(d,p) and B3 LYP/c PVTZ. Some energies and molecular orbital properties are obtained. The structures are found to be stable in the singlet state but mostly unstable in the triplet. The heats of formation values calculated by means of T1 recipe reveals that they are highly endothermic. NICS(0) values have been calculated and aromaticity/antiaromaticity of the rings are discussed. Additionally, theoretical IR,UV-VIS spectra and the calculated impulse values have been obtained.展开更多
Basing on the DFT calculations we propose the new theoretical model which describes both the surface tension σ of the short chain n-alkanes at their normal boiling points and their reaction rate constants with hydrox...Basing on the DFT calculations we propose the new theoretical model which describes both the surface tension σ of the short chain n-alkanes at their normal boiling points and their reaction rate constants with hydroxyl radicals OH<span style="white-space:nowrap;">• (at 297 ± 2 K) on the basis of their molecular orbital electronic characteristics. It has been shown that intermolecular dispersion attraction within the surface liquid monolayer of these compounds, as well as their reaction rate constants k with OH<span style="white-space:nowrap;">• radicals are determined by the energies E<sub>orb</sub> of the specific occupied molecular orbitals which are the same in the determination of both the above physico-chemical characteristics of the studied n-alkanes. The received regression equations confirm the theoretically found dependences between the quantities of σ and k and the module |E<sub>orb</sub>|. For the compounds under study this fact indicates the key role of their electronic structure particularities in determination of both the physical (surface tension) and the chemical (reaction rate constants) properties.展开更多
The mechanism and related reaction paths in the hydroisomerization of n-pentane were studied by DFT calculations at the B3LYP/6-311＋＋G^＊＊ level. Two possible transition states were theoretically predicted and ve...The mechanism and related reaction paths in the hydroisomerization of n-pentane were studied by DFT calculations at the B3LYP/6-311＋＋G^＊＊ level. Two possible transition states were theoretically predicted and verified by the vibration frequency analysis as well as the calculations of intrinsic reaction coordinates （IRC）. Furthermore, the related reaction barriers were evaluated by single point energy at the MP2/6-311＋＋G^＊＊ level with zero point vibration correction of DFT method. Thus, it is concluded that the isomerization might go through two pathways.展开更多
Nowadays, the main effort of the scientific community is focused on the search of specific drugs for the inhibition of the Severe Acute Respiratory Syndrome—Coronavirus 2 (SARS-CoV-2), which is responsible for the Co...Nowadays, the main effort of the scientific community is focused on the search of specific drugs for the inhibition of the Severe Acute Respiratory Syndrome—Coronavirus 2 (SARS-CoV-2), which is responsible for the Coro-navirus Disease 19 or COVID-19. With the same objective in mind, a Molecular Docking study was performed in this work in order to discover information about some antiviral drugs of common use as protease inhibitors. As a complement of this research, a chemical reactivity study of these potential drugs was done with the aim of finding a relationship between the inhibition ability and the chemical reactivity. The results presented in this research constitute one of the first predictions aimed to identify the best potential compounds for this purpose while at the same time verifying the validity of the employed theoretical and computational methodology. By means of the analysis of the number of hydrogen bonds as well as the binding energies coming from the Molecular Docking study, it can be said that Telaprevir, Nelfinavir and Indinavir have the highest probability of success as potential inhibitors of SARS-CoV-2.展开更多
From our DFT calculations of Ibuprofen drug (IBF) and other related molecules such as 2-Phenylpropanoic acid (2-PPA) and 3-Phenylpropanoic acid (3-PPA), it has been found that the ionization potential energies of thei...From our DFT calculations of Ibuprofen drug (IBF) and other related molecules such as 2-Phenylpropanoic acid (2-PPA) and 3-Phenylpropanoic acid (3-PPA), it has been found that the ionization potential energies of their anions are decreased strongly, with respect to their values in the molecular forms, rendering them as spontaneous electron donor which can compensate the electron deficiency for the positive cancer cells. Time dependent calculations show good coincidence with the experimental absorption spectra. Some complexes of IBF are prepared with Cu<sup>++</sup> and Zn<sup>++</sup> ions. The ratio between the M<sup>++</sup> and the ligand (IBF) is 1:2 which has been verified by atomic absorption spectra and elemental analyses. Their spectral studies have been performed in different solvents of different polarities. The metabolite products of IBF have been studied from DFT calculations point of view and it has been concluded that the consistency of the ionization constants and the electron affinities of them with those of the nucleic acid bases prevents the electron transfer between them therefore they are safe for the human body from cancer diseases.展开更多
调制解调法是一种常用的微弱信号检测方法,高精度、低复杂度的解调方法的实现对于调制解调法的应用具有重要的意义.传统坐标旋转数字计算(coordinate rotation digital computer,CORDIC)算法具有占用资源多,需要缩放因子补偿等问题.因...调制解调法是一种常用的微弱信号检测方法,高精度、低复杂度的解调方法的实现对于调制解调法的应用具有重要的意义.传统坐标旋转数字计算(coordinate rotation digital computer,CORDIC)算法具有占用资源多,需要缩放因子补偿等问题.因此设计并实现了一种基于改进CORDIC算法的离散傅里叶变换(discrete Fourier transform,DFT)解调方法用于微弱信号的检测.首先改进了传统的CORDIC算法用于正余弦函数值的计算,该方法不仅免除了缩放因子,而且不需要进行旋转角度的判断,降低了算法的资源占用;然后基于该CORDIC算法设计了DFT解调算法,避免了乘法器与大量查找表的使用.最终仿真结果表明,设计的DFT解调方法在整周期采样的情况下能够实现对调制信号的高精度解调,并且具备良好的抗噪声性能,能够满足微弱信号检测的要求.展开更多
Cis-and trans-1,3,4,6-tetranitroglycouril(TNGU, Sorguyl) have been considered for density functional treatment at the levels of B3LYP/6-31 G(d,p) and B3LYP/cc-PVDZ. Cis-TNGU has been found to be more stable than its t...Cis-and trans-1,3,4,6-tetranitroglycouril(TNGU, Sorguyl) have been considered for density functional treatment at the levels of B3LYP/6-31 G(d,p) and B3LYP/cc-PVDZ. Cis-TNGU has been found to be more stable than its trans isomer. Then, mono and dialuminized(cis-TNGU + Al and cis-TNGU+2Al) have been subjected to theoretical treatment at the level of B3LYP/6-31 + G(d). The spin states of the aluminized cis-TNGU composites have been considered as well. Although, cis-TNGU + Al(doublet) is found to be structurally stable, cis-TNGU+2Al singlet and triplet composites undergo certain bond cleavages.Structural and some quantum chemical properties, IR-UV spectra etc. have been presented.展开更多
Isomers of trans-1,4-Dinitroglycoluril(trans-DINGU) and their 1,3-tautomers are considered within the constraints of B3LYP/6-31ttG(d,p) and B3LYP/CC-PVTZ levels of DFT calculations. Additionally, the interactions of t...Isomers of trans-1,4-Dinitroglycoluril(trans-DINGU) and their 1,3-tautomers are considered within the constraints of B3LYP/6-31ttG(d,p) and B3LYP/CC-PVTZ levels of DFT calculations. Additionally, the interactions of these isomers and proton in vacuum are investigated. The data have revealed that two of the three isomers undergo C — H bond cleavage as the result of interaction with proton in vacuum. The total energies, some structural properties, the calculated IR and UV spectra are discussed.展开更多
Metal complexes bearing vic-dioxime ligands have been extensively used as analytical and biochemical reagents, and are well-known antimicrobial agents. Herein is reported a DFT study on the molecular structures, therm...Metal complexes bearing vic-dioxime ligands have been extensively used as analytical and biochemical reagents, and are well-known antimicrobial agents. Herein is reported a DFT study on the molecular structures, thermodynamic properties, chemical reactivity and spectral properties of some 3d metal(II) chloride complexes of glyoxime. The functionals B3LYP and CAM-B3LYP have each been used in conjunction with LANL2DZ for the metal(II) ions (Fe<sup>2+</sup>, Co<sup>2+</sup>, Ni<sup>2+</sup> and Cu<sup>2+</sup>) and the Poplestyle basis set 6-31G+(d,p) for the rest of the elements, to perform theoretical calculations. The metal complexation abilities of the glyoxime ligands studied in this work have been evaluated on the basis of metal-ligand binding energies. These ligands were found to have high affinities towards Ni(II) and Fe(II) ions, and all complexation reactions were found to be thermodynamically feasible. Ligand-to-metal electron donations in the complexes studied have been revealed by natural population analysis. The fully optimized geometries of the complexes have adopted square planar structures around the central metal ions. On the basis of orbital composition analysis, the UV-Vis electronic absorption bands of these molecules have been attributed mainly to MLCT, LMCT and d-d electronic transitions involving metal-based orbitals.展开更多
基金financial support to conduct this research from the Science and Engineering Research Board(SERB)through a state university research excellence(SURE)grant(SUR/2022/004935).
文摘Density functional theory(DFT)calculations were employed to investigate the adsorption behavior of NH_(3),AsH_(3),PH_(3),CO_(2),and CH_(4)molecules on both pristine and mono-vacancy phosphorene sheets.The pristine phosphorene surface showsweak physisorption with all the gasmolecules,inducing onlyminor changes in its structural and electronic properties.However,the introduction ofmono-vacancies significantly enhances the interaction strength with NH_(3),PH_(3),CO_(2),and CH_(4).These variations are attributed to substantial charge redistribution and orbital hybridization in the presence of defects.The defective phosphorene sheet also exhibits enhanced adsorption energies,along with favorable sensitivity and recovery characteristics,highlighting its potential as a promising gas sensor for NH_(3),AsH_(3),PH_(3),CO_(2),and CH_(4)at ambient conditions.
基金supported by the National Key Research and Development Program of China (Grant No. 2024YFB4205101)the National Natural Science Foundation of China (No. 62274098 and No. 62074084)+2 种基金the Natural Science Foundation of Tianjin (No.22JCYBJC01300, No. 23JCYBJC01620 and No. 21JCYBJC00270)the Overseas Expertise Introduction Project for Discipline Innovation of Higher Edu cation of China (Grant No. B16027)the Fundamental Research Funds for the Central Universities,Nankai University (No. 63241568)
文摘Efficient surface passivation is critical for achieving high-performance perovskite solar cells(PSCs),yet the discovery of optimal passivators remains a time-consuming,trial-and-error process.Here,we report a synergistic machine learning(ML)and density functional theory(DFT)approach that enables predictive and rapid identification of effective passivation materials.By training an XGBoost model(91.3%accuracy)with DFT-derived molecular descriptors and activity calculations,we identify 2-(4-aminophenyl)-3H-benzimidazol-5-amine(APBIA)as a promising passivator.Experimental validation demonstrates that APBIA effectively removes surface impurities and passivates defects within perovskite films,leading to a significant increase in power conversion efficiency(PCE)from 22.48%to 25.55%(certified as 25.02%).This ML-DFT framework provides a generalizable pathway for accelerating the development of advanced functional materials for photovoltaic applications.
文摘Cis-trans isomerization of [9]-annulenanion（1） and its 2-fluoro-,2-chloro-and 2-bromo-derivatives（2,3 and 4,respectively） were investigated at the HF/6-31G＊ and B3LYP/6-311＋＋G＊＊ levels of theory.Cis,cis,cis,cis structures appear more stable than their corresponding cis,cis,cis,trans-isomers.The relative height of energy barriers for cis-trans isomerization is：2cis 〉1cis 〉3cis〉 4cis.This trend for the reverse trans-cis isomerization follows the electronegativity of the substituent at C-2（2trans 3trans 4trans 1trans）.
文摘Various cyclic N_8 isomers are considered at the levels of B3 LYP/6-311++G(d,p) and B3 LYP/c PVTZ. Some energies and molecular orbital properties are obtained. The structures are found to be stable in the singlet state but mostly unstable in the triplet. The heats of formation values calculated by means of T1 recipe reveals that they are highly endothermic. NICS(0) values have been calculated and aromaticity/antiaromaticity of the rings are discussed. Additionally, theoretical IR,UV-VIS spectra and the calculated impulse values have been obtained.
文摘Basing on the DFT calculations we propose the new theoretical model which describes both the surface tension σ of the short chain n-alkanes at their normal boiling points and their reaction rate constants with hydroxyl radicals OH<span style="white-space:nowrap;">• (at 297 ± 2 K) on the basis of their molecular orbital electronic characteristics. It has been shown that intermolecular dispersion attraction within the surface liquid monolayer of these compounds, as well as their reaction rate constants k with OH<span style="white-space:nowrap;">• radicals are determined by the energies E<sub>orb</sub> of the specific occupied molecular orbitals which are the same in the determination of both the above physico-chemical characteristics of the studied n-alkanes. The received regression equations confirm the theoretically found dependences between the quantities of σ and k and the module |E<sub>orb</sub>|. For the compounds under study this fact indicates the key role of their electronic structure particularities in determination of both the physical (surface tension) and the chemical (reaction rate constants) properties.
基金Supported by the Foundation of Education Committee of Liaoning Province (No. 990321076)
文摘The mechanism and related reaction paths in the hydroisomerization of n-pentane were studied by DFT calculations at the B3LYP/6-311＋＋G^＊＊ level. Two possible transition states were theoretically predicted and verified by the vibration frequency analysis as well as the calculations of intrinsic reaction coordinates （IRC）. Furthermore, the related reaction barriers were evaluated by single point energy at the MP2/6-311＋＋G^＊＊ level with zero point vibration correction of DFT method. Thus, it is concluded that the isomerization might go through two pathways.
文摘Nowadays, the main effort of the scientific community is focused on the search of specific drugs for the inhibition of the Severe Acute Respiratory Syndrome—Coronavirus 2 (SARS-CoV-2), which is responsible for the Coro-navirus Disease 19 or COVID-19. With the same objective in mind, a Molecular Docking study was performed in this work in order to discover information about some antiviral drugs of common use as protease inhibitors. As a complement of this research, a chemical reactivity study of these potential drugs was done with the aim of finding a relationship between the inhibition ability and the chemical reactivity. The results presented in this research constitute one of the first predictions aimed to identify the best potential compounds for this purpose while at the same time verifying the validity of the employed theoretical and computational methodology. By means of the analysis of the number of hydrogen bonds as well as the binding energies coming from the Molecular Docking study, it can be said that Telaprevir, Nelfinavir and Indinavir have the highest probability of success as potential inhibitors of SARS-CoV-2.
文摘From our DFT calculations of Ibuprofen drug (IBF) and other related molecules such as 2-Phenylpropanoic acid (2-PPA) and 3-Phenylpropanoic acid (3-PPA), it has been found that the ionization potential energies of their anions are decreased strongly, with respect to their values in the molecular forms, rendering them as spontaneous electron donor which can compensate the electron deficiency for the positive cancer cells. Time dependent calculations show good coincidence with the experimental absorption spectra. Some complexes of IBF are prepared with Cu<sup>++</sup> and Zn<sup>++</sup> ions. The ratio between the M<sup>++</sup> and the ligand (IBF) is 1:2 which has been verified by atomic absorption spectra and elemental analyses. Their spectral studies have been performed in different solvents of different polarities. The metabolite products of IBF have been studied from DFT calculations point of view and it has been concluded that the consistency of the ionization constants and the electron affinities of them with those of the nucleic acid bases prevents the electron transfer between them therefore they are safe for the human body from cancer diseases.
文摘Cis-and trans-1,3,4,6-tetranitroglycouril(TNGU, Sorguyl) have been considered for density functional treatment at the levels of B3LYP/6-31 G(d,p) and B3LYP/cc-PVDZ. Cis-TNGU has been found to be more stable than its trans isomer. Then, mono and dialuminized(cis-TNGU + Al and cis-TNGU+2Al) have been subjected to theoretical treatment at the level of B3LYP/6-31 + G(d). The spin states of the aluminized cis-TNGU composites have been considered as well. Although, cis-TNGU + Al(doublet) is found to be structurally stable, cis-TNGU+2Al singlet and triplet composites undergo certain bond cleavages.Structural and some quantum chemical properties, IR-UV spectra etc. have been presented.
文摘Isomers of trans-1,4-Dinitroglycoluril(trans-DINGU) and their 1,3-tautomers are considered within the constraints of B3LYP/6-31ttG(d,p) and B3LYP/CC-PVTZ levels of DFT calculations. Additionally, the interactions of these isomers and proton in vacuum are investigated. The data have revealed that two of the three isomers undergo C — H bond cleavage as the result of interaction with proton in vacuum. The total energies, some structural properties, the calculated IR and UV spectra are discussed.
文摘Metal complexes bearing vic-dioxime ligands have been extensively used as analytical and biochemical reagents, and are well-known antimicrobial agents. Herein is reported a DFT study on the molecular structures, thermodynamic properties, chemical reactivity and spectral properties of some 3d metal(II) chloride complexes of glyoxime. The functionals B3LYP and CAM-B3LYP have each been used in conjunction with LANL2DZ for the metal(II) ions (Fe<sup>2+</sup>, Co<sup>2+</sup>, Ni<sup>2+</sup> and Cu<sup>2+</sup>) and the Poplestyle basis set 6-31G+(d,p) for the rest of the elements, to perform theoretical calculations. The metal complexation abilities of the glyoxime ligands studied in this work have been evaluated on the basis of metal-ligand binding energies. These ligands were found to have high affinities towards Ni(II) and Fe(II) ions, and all complexation reactions were found to be thermodynamically feasible. Ligand-to-metal electron donations in the complexes studied have been revealed by natural population analysis. The fully optimized geometries of the complexes have adopted square planar structures around the central metal ions. On the basis of orbital composition analysis, the UV-Vis electronic absorption bands of these molecules have been attributed mainly to MLCT, LMCT and d-d electronic transitions involving metal-based orbitals.
