The geometry structures of 6 triazolone compounds containing benzenesulfonic amide were fully optimized with DFT （Density Functional Theory） method at the B3LYP/6-31G level, and the structural and electronic paramet...The geometry structures of 6 triazolone compounds containing benzenesulfonic amide were fully optimized with DFT （Density Functional Theory） method at the B3LYP/6-31G level, and the structural and electronic parameters of the compounds were calculated. The hydrophobic and topological parameters of the title compounds were calculated by HyperChem software. The mono- and bi-parametric models between the parameters and biological activity of the compounds were analyzed by Multiple Linear Regression method based on Hansch-Fujita model. The results show that the activities of the title compounds were increased with higher hydrophobic property logP and molecular volume V, lower molecular energy ETOTAL and electronegative of benzene ring Qph.展开更多
The geometries, vibrational frequencies and bind energies are reported for the ground states of CaC 2H + 2, CaC 2D + 2 and CaC 2H + 4. CaC 2H + 2 and CaC 2H + 4 equilibrium geometries have C 2v symmetry with the metal...The geometries, vibrational frequencies and bind energies are reported for the ground states of CaC 2H + 2, CaC 2D + 2 and CaC 2H + 4. CaC 2H + 2 and CaC 2H + 4 equilibrium geometries have C 2v symmetry with the metal ion lying in the perpendicular bisector of the C-C bond. The ground state in both CaC 2H + 2 and CaC 2H + 4 molecules ia a 2A 1 state and the binding in the ground state is mainly electrostatic. For both CaC 2H + 2 and CaC 2H + 4 the ligand is only slightly distorted from its free ligand structure, the C-C distance has hardly increased and there is only a very small bending of the H atom away from the Ca atom. This is consistent with the electrostatic nature of the bonding. Two different approaches-Hartree-Fock(HF) and density functional theory methods(DFT)-are used and basis sets here used is 6-311+G(3df,2p). The DFT results are in good agreement with experiments, namely, DFT methods provide the benefits that some more expensive ab initio methods can do, but at essentially HF cost. So it is important to include electron correlation for accurate results in this study.展开更多
As a large family of 2D materials, transition metal dichalcogenides(TMDs) have stimulated numerous works owing to their attractive properties. The replacement of constituent elements could promote the discovery and fa...As a large family of 2D materials, transition metal dichalcogenides(TMDs) have stimulated numerous works owing to their attractive properties. The replacement of constituent elements could promote the discovery and fabrication of new nanofilm in this family. Using precious metals, such as platinum and palladium, to serve as transition metals combined with chalcogen is a new approach to explore novel TMDs. Also, the proportion between transition metal and chalcogen atoms is found not only to exist in conventional form of 1 : 2. Herein, we reported a comprehensive study of a new 2D precious metal selenide, namely AuSe monolayer. Based on density functional theory, our result indicated that AuSe monolayer is a semiconductor with indirect band-gap of 2.0 eV, which possesses superior dynamic stability and thermodynamic stability with cohesive energy up to–7.87 eV/atom. Moreover, it has been confirmed that ionic bonding predominates in Au–Se bonds and absorption peaks in all directions distribute in the deep ultraviolet region. In addition, both vibration modes dominating marked Raman peaks are parallel to the 2D plane.展开更多
The electronic and optical properties of 2D Cu_2Si and Cu_2Si:Ti are investigated based on the density functional theory(DFT) using the FP-LAPW method and GGA approximation. The 2D Cu_2Si has metallic and non magnetic...The electronic and optical properties of 2D Cu_2Si and Cu_2Si:Ti are investigated based on the density functional theory(DFT) using the FP-LAPW method and GGA approximation. The 2D Cu_2Si has metallic and non magnetic properties, whereas adding Ti impurity to its structure changes the electronic behavior to the half-metallic with 3.256μB magnetic moment. The optical transition is not occurred in the infrared and visible area for the 2D Cu_2Si in x-direction and by adding Ti atom, the real part of dielectric function in the x-direction, Re(ε(ω))_x is reached to a Dirac peak at this energy range. Moreover, the absorption gap tends to zero in x-direction of the 2D Cu_2Si:Ti.展开更多
High carrier mobility and a direct semiconducting band gap are two key properties of materials for elec- tronic device applications. Using first-principles calculations, we predict two types of two-dimensional semicon...High carrier mobility and a direct semiconducting band gap are two key properties of materials for elec- tronic device applications. Using first-principles calculations, we predict two types of two-dimensional semiconductors, ultrathin GeAsSe and SnSbTe nanosheets, with desirable electronic and optical prop- erties. Both GeAsSe and SnSbTe sheets are energetically favorable, with formation energies of -0.19 anti -0.09 eV/atom, respectively, and have excellent dynamical and thermal stability, as determined by phonon dispersion calculations and Born-Oppenheimer molecular dynamics simulations. The rel- atively weak interlayer binding energies suggest that these monolayer sheets can be easily exfoliated from the bulk crystals. Importantly, monolayer GeAsSe and SnSbTe possess direct band gaps （2.56 and 1.96 eV, respectively） and superior hole mobility （- 20 000 cm2.V-1.s-1）, and both exhibit notable absorption in the visible region. A comparison of the band edge positions with the redox potentials of water reveals that layered GeAsSe and SnSbTe are potential photocatalysts for water splitting. These exceptional properties make layered GeAsSe and SnSbTe promising candidates for use in future high-speed electronic and optoelectronic devices.展开更多
Electronic properties of stanene, the Sn counterpart of graphene are theoretically studied using first-principles simulations. The topological to trivial insulating phase transition induced by an out-of-plane electric...Electronic properties of stanene, the Sn counterpart of graphene are theoretically studied using first-principles simulations. The topological to trivial insulating phase transition induced by an out-of-plane electric field or by quantum confinement effects is predicted. The results highlight the potential to use stanene nanoribbons in gate-voltage controlled dissipationless spin-based devices and are used to set the minimal nanoribbon width for such devices, which is typically approximately 5 nm.展开更多
基金This work was supported by talents in University (NCET-04-0649)the Natural Science Foundation of Shandong Province (Y2006B07, Z2006B01)
文摘The geometry structures of 6 triazolone compounds containing benzenesulfonic amide were fully optimized with DFT （Density Functional Theory） method at the B3LYP/6-31G level, and the structural and electronic parameters of the compounds were calculated. The hydrophobic and topological parameters of the title compounds were calculated by HyperChem software. The mono- and bi-parametric models between the parameters and biological activity of the compounds were analyzed by Multiple Linear Regression method based on Hansch-Fujita model. The results show that the activities of the title compounds were increased with higher hydrophobic property logP and molecular volume V, lower molecular energy ETOTAL and electronegative of benzene ring Qph.
文摘The geometries, vibrational frequencies and bind energies are reported for the ground states of CaC 2H + 2, CaC 2D + 2 and CaC 2H + 4. CaC 2H + 2 and CaC 2H + 4 equilibrium geometries have C 2v symmetry with the metal ion lying in the perpendicular bisector of the C-C bond. The ground state in both CaC 2H + 2 and CaC 2H + 4 molecules ia a 2A 1 state and the binding in the ground state is mainly electrostatic. For both CaC 2H + 2 and CaC 2H + 4 the ligand is only slightly distorted from its free ligand structure, the C-C distance has hardly increased and there is only a very small bending of the H atom away from the Ca atom. This is consistent with the electrostatic nature of the bonding. Two different approaches-Hartree-Fock(HF) and density functional theory methods(DFT)-are used and basis sets here used is 6-311+G(3df,2p). The DFT results are in good agreement with experiments, namely, DFT methods provide the benefits that some more expensive ab initio methods can do, but at essentially HF cost. So it is important to include electron correlation for accurate results in this study.
基金financially supported by the Natural Science Foundation of Jiangsu Province(No.BK20180071)the Fundamental Research Funds for the Central Universities(No.30919011109)PAPD of Jiangsu Higher Education Institutions
文摘As a large family of 2D materials, transition metal dichalcogenides(TMDs) have stimulated numerous works owing to their attractive properties. The replacement of constituent elements could promote the discovery and fabrication of new nanofilm in this family. Using precious metals, such as platinum and palladium, to serve as transition metals combined with chalcogen is a new approach to explore novel TMDs. Also, the proportion between transition metal and chalcogen atoms is found not only to exist in conventional form of 1 : 2. Herein, we reported a comprehensive study of a new 2D precious metal selenide, namely AuSe monolayer. Based on density functional theory, our result indicated that AuSe monolayer is a semiconductor with indirect band-gap of 2.0 eV, which possesses superior dynamic stability and thermodynamic stability with cohesive energy up to–7.87 eV/atom. Moreover, it has been confirmed that ionic bonding predominates in Au–Se bonds and absorption peaks in all directions distribute in the deep ultraviolet region. In addition, both vibration modes dominating marked Raman peaks are parallel to the 2D plane.
基金Supported by Islamic Azad University,Kermanshah branch,Kermanshah,Iran
文摘The electronic and optical properties of 2D Cu_2Si and Cu_2Si:Ti are investigated based on the density functional theory(DFT) using the FP-LAPW method and GGA approximation. The 2D Cu_2Si has metallic and non magnetic properties, whereas adding Ti impurity to its structure changes the electronic behavior to the half-metallic with 3.256μB magnetic moment. The optical transition is not occurred in the infrared and visible area for the 2D Cu_2Si in x-direction and by adding Ti atom, the real part of dielectric function in the x-direction, Re(ε(ω))_x is reached to a Dirac peak at this energy range. Moreover, the absorption gap tends to zero in x-direction of the 2D Cu_2Si:Ti.
基金This work was supported by the National Natural Science Foundation of China （Grant No. 11574040）, the Fundamental Research Funds for tile Central Universities of China （Grant Nos. DUT16-LAB01 and DUT17LAB19）. Y. G. was supported by China Scholarship Council （CSC, Grant No. 201706060138）. X. C. Z. was supported by the National Science Foundation （NSF） through the Nebraska Materials Research Science and Engineering Center （MRSEC） （Grant No. DMR- 1420645）. We acknowledge the computing resource from the Su- percomputing Center of Dalian University of Technology and the University of Nebraska Holland Computing Center.
文摘High carrier mobility and a direct semiconducting band gap are two key properties of materials for elec- tronic device applications. Using first-principles calculations, we predict two types of two-dimensional semiconductors, ultrathin GeAsSe and SnSbTe nanosheets, with desirable electronic and optical prop- erties. Both GeAsSe and SnSbTe sheets are energetically favorable, with formation energies of -0.19 anti -0.09 eV/atom, respectively, and have excellent dynamical and thermal stability, as determined by phonon dispersion calculations and Born-Oppenheimer molecular dynamics simulations. The rel- atively weak interlayer binding energies suggest that these monolayer sheets can be easily exfoliated from the bulk crystals. Importantly, monolayer GeAsSe and SnSbTe possess direct band gaps （2.56 and 1.96 eV, respectively） and superior hole mobility （- 20 000 cm2.V-1.s-1）, and both exhibit notable absorption in the visible region. A comparison of the band edge positions with the redox potentials of water reveals that layered GeAsSe and SnSbTe are potential photocatalysts for water splitting. These exceptional properties make layered GeAsSe and SnSbTe promising candidates for use in future high-speed electronic and optoelectronic devices.
文摘Electronic properties of stanene, the Sn counterpart of graphene are theoretically studied using first-principles simulations. The topological to trivial insulating phase transition induced by an out-of-plane electric field or by quantum confinement effects is predicted. The results highlight the potential to use stanene nanoribbons in gate-voltage controlled dissipationless spin-based devices and are used to set the minimal nanoribbon width for such devices, which is typically approximately 5 nm.
