The electric field effect in ultrathin zigzag graphene nanoribbons containing only three or four zigzag carbon chains is studied by first-principles calculations, and the change of conducting mechanism is observed wit...The electric field effect in ultrathin zigzag graphene nanoribbons containing only three or four zigzag carbon chains is studied by first-principles calculations, and the change of conducting mechanism is observed with increasing in-plane electric field perpendicular to the ribbon. Wider zigzag graphene nanoribbons have been predicted to be spin-splitted for both valence band maximum（VBM） and conduction band minimum（CBM） with an applied electric field and become half-metal due to the vanishing band gap of one spin with increasing applied field. The change of VBM for the ultrathin zigzag graphene nanoribbons is similar to that for the wider ones when an electric field is applied. However, in the ultrathin zigzag graphene nanoribbons, there are two kinds of CBMs, one is spin-degenerate and the other is spin-splitted, and both are tunable by the electric field. Moreover, the two CBMs are spatially separated in momentum space. The conducting mechanism changes from spin-degenerate CBM to spin-splitted CBM with increasing applied electric field. Our results are confirmed by density functional calculations with both LDA and GGA functionals, in which the LDA always underestimates the band gap while the GGA normally produces a bigger band gap than the LDA.展开更多
Dioxin is a highly toxic and caustic substance,which widely existed in the atmosphere,soil and water with tiny particles.Dioxin pollution has become a major problem that concerns the survival of mankind,which must be ...Dioxin is a highly toxic and caustic substance,which widely existed in the atmosphere,soil and water with tiny particles.Dioxin pollution has become a major problem that concerns the survival of mankind,which must be strictly controlled.The bond length,bond angle,energy,dipole moment,orbital energy level distribution of dioxin under the external field are investigated using DFT(density functional theory)on basis set level of B3LYP/6-31G(d,p).The results indicate that with the increase of the electric field,the length of one Carbon-Oxygen bond increases while another Carbon-Oxygen bond decreases.The energy gradually decreases with the electric field,while the change of the dipole moment has an opposite trend.In the infrared spectra,the vibration frequency decreases with the electric field increasing and shows an obvious red shift.Moreover,the ultraviolet-visible absorption spectra under different electric fields are analyzed with TD-DFT(time-dependent density functional theory)method.The wavelength of the strongest absorption peak increases and occurs red shift with the increase of the electric field.All the above results can provide reference for further research on the properties of dioxin under different external electric field.展开更多
Geometry and vibrational frequencies of the ground state of Si2O2 molecule are studied using density function theory （DFT） at the level of cc-pvtz and 6-311-k＋G^＊＊. It is found that the optimizing value by B31yp/...Geometry and vibrational frequencies of the ground state of Si2O2 molecule are studied using density function theory （DFT） at the level of cc-pvtz and 6-311-k＋G^＊＊. It is found that the optimizing value by B31yp/cc-pvtz is closer to the experimental data. The excited properties under different external electric fields are also investigated by the time-dependent-DFT method. Transitions from the ground state of Si2O2 molecule to the first singlet state under different external electric fields can take place more easily. The corresponding absorption spectral line is about 360 nm in wavelength and the excitation energy is about 3.4 eV.展开更多
Disulfur dichloride is a hazardous substance, which is irritating to the eyes. It is significant to study the physical and dissociation properties under external electric fields. The bond length, energy, dipole moment...Disulfur dichloride is a hazardous substance, which is irritating to the eyes. It is significant to study the physical and dissociation properties under external electric fields. The bond length, energy, dipole moment, orbital energy level distribution, infrared spectra and dissociation properties of disulfur dichloride molecule under different external fields are obtained by using the density functional theory at the B3LYP/6-311++G(d, p) basis set level. In addition, ultraviolet-visible absorption spectra of the molecule in different electric fields are studied with configuration interaction-single excitation(CIS)/6-311++G(d, p) method. According to the results, it has been found that as the electric field exerted along the positive direction of the z-axis increases, the two sulfur-chlorine(S-Cl) bond lengths become longer and tend to break, while the sulfur-sulfur(S-S) bond length becomes shorter and the energy gap decreases. The infrared spectrum and ultraviolet-visible absorption spectra both exhibit red shift under electric field. Moreover, by scanning the potential energy surface of disulfur dichloride about S-Cl bond, the dissociation barrier decreases with the increase of positive electric field. When the external electric field arrives at 0.040 atomic units, the barrier disappears, meaning the dissociation of disulfur dichloride. The present results offer an important reference to further study of disulfur dichloride.展开更多
Although the performance of the self-standing electrode has been enhanced for aqueous zinc-ion batteries(AZIBs),it is necessary to explore and analyse the deep modification mechanism(especially interface effects).Here...Although the performance of the self-standing electrode has been enhanced for aqueous zinc-ion batteries(AZIBs),it is necessary to explore and analyse the deep modification mechanism(especially interface effects).Herein,density functional theory(DFT)calculations are applied to investigate the high-performance cathode based on the VO_(2)/carbon cloth composites with heterostructures interface(H-VO_(2)@CC).The adsorption energy comparisons and electron structure analyses verify that HVO_(2)@CC has extra activated sites at the interface,enhanced electrical conductivity,and structural stability for achieving highperformance AZIBs due to the presence of built-in electric field at the interfaces.Accordingly,the designed self-standing HVO_(2)@CC cathode delivers higher rate capacity,longer-life cyclability,and faster electronic/ion transmission kinetics benefiting from the synergistic effects.The risks of active material shedding and dissolution during the dis/charge process of two cathodes were evaluated via ex-situ ultraviolet–visible(UV–vis)spectrum and inductively coupled plasma-atomic emission spectroscopy(ICP-AES)technique.Finally,this investigation also explores the charge storage mechanism of H-VO_(2)@CC through various exsitu and in-situ characterization techniques.This finding can shed light on the significant potential of heterostructures interface engineering in practical applications and provide a valuable direction for the development of cathode materials for AZIBs and other metal-ion batteries.展开更多
The autocorrelation function of electronic wave packet of hydrogen atom in a strong electric field below the zero-field ionization threshold is investigated in the formalism of semiclassical theory. It is found that t...The autocorrelation function of electronic wave packet of hydrogen atom in a strong electric field below the zero-field ionization threshold is investigated in the formalism of semiclassical theory. It is found that the autocorrelation depends on the applied laser pulse significantly. In the case of narrow laser pulse, the reviving peaks in the autocorrelation can be attributed to the closed orbits of electrons, which are related to the classical dynamics of the system. But this correspondence is wiped out with increasing the laser width because of the interference among the adjacent reviving peaks.展开更多
Several bare zigzag phosphorene nanoribbons with odd number of atoms in the direction perpendicular to the extended line are investigated by using HSE06 density functional theory.These nanoribbons are as stable as tho...Several bare zigzag phosphorene nanoribbons with odd number of atoms in the direction perpendicular to the extended line are investigated by using HSE06 density functional theory.These nanoribbons are as stable as those with even number of atoms.Primitive cells of the nanoribbons are metals,while edge self-passivation and distortion in the supercell structures cause metal-semiconductor transition.The band gaps of semiconducting nanoribbons are around 0.4 eV,which is enough for high on/off ratio in device operation.Compared to the conduction bands,the valence bands have smaller deformation potential constants and larger band width.Thus,the hole mobilities of the nanoribbons（10 cm^2·V^（-1）·s^（-1）） are one order higher than the electron mobilities.Bare zigzag phosphorene nanoribbons with odd number of atoms can also be candidates for small-size high-speed electronic devices.展开更多
Oxalyl chloride is a highly toxic and caustic substance, which widely exists in human production and life as a kind of volatile organic compound. Based on the density functional theory B3 LYP at 6-311++G(d, p) level, ...Oxalyl chloride is a highly toxic and caustic substance, which widely exists in human production and life as a kind of volatile organic compound. Based on the density functional theory B3 LYP at 6-311++G(d, p) level, the influences of external electric field on the bond length, bond energy, dipole moment and dissociation mechanism are optimized. The results indicate that the C_1–Cl_3 bond length increases while the C_4–Cl_6 bond decreases. At the same time, the carbon-carbon bond length gradually increases with the increase of electric field. The total energy decreases while the dipole moment gradually increases with the increase of electric field. In the infrared spectra, the vibration frequency of the carbon-chlorine(C_4–Cl_6) bond decreases while the vibration frequency of the carbon-oxygen bond increases. In the ultraviolet-visible spectra, the wavelength of the strongest absorption peak increases as the external electric field increases and shows an observable red shift phenomenon. Additionally, single point energies of oxalyl chloride along the carbon-carbon bond are scanned with the equation-of-motion coupled cluster method restricted to single and double excitations(EOM-CCSD) method and the potential energy curves under different external electric fields are obtained. The dissociation barrier in potential energy curve decreases because of the breakage of carbon-carbon bond with the increase of external electric field. These results provide reference for further researches on the properties of oxalyl chloride and offer a theoretical basis for the study of oxalyl chloride degradation.展开更多
The structural and electronic properties of a(4,0) zigzag single-walled carbon nanotube(SWCNT) under parallel and transverse electric fields with strengths of 0-1.4×10-2 a.u.were studied using the density functio...The structural and electronic properties of a(4,0) zigzag single-walled carbon nanotube(SWCNT) under parallel and transverse electric fields with strengths of 0-1.4×10-2 a.u.were studied using the density functional theory(DFT) B3LYP/6-31G* method.Results show that the properties of the SWCNT are dependent on the external electric field.The applied external electric field strongly affects the molecular dipole moments.The induced dipole moments increase linearly with increase in the electrical field intensities.This study shows that the application of parallel and transverse electric fields results in changes in the occupied and virtual molecular orbitals(MOs) but the energy gap between the highest occupied MO(HOMO) and the lowest unoccupied MO(LUMO) of this SWCNT is less sensitive to the electric field strength.The electronic spatial extent(ESE) and length of the SWCNT show small changes over the entire range of the applied electric field strengths.The natural bond orbital(NBO) electric charges on the atoms of the SWCNT show that increase in the external electric field strength increases the separation of the center of the positive and negative electric charges of the carbon nanotube.展开更多
Zigzag graphene nanoribbons(ZGNRs)with spin-polarized edge states have potential applications in carbon-based spintronics.The electronic structure of ZGNRs can be effectively tuned by different widths or dopants,which...Zigzag graphene nanoribbons(ZGNRs)with spin-polarized edge states have potential applications in carbon-based spintronics.The electronic structure of ZGNRs can be effectively tuned by different widths or dopants,which requires delicately designed monomers.Here,we report the successful synthesis of ZGNR with a width of eight carbon zigzag lines and nitrogen-boronnitrogen(NBN)motifs decorated along the zigzag edges(NBN-8-ZGNR)on Au(111)surface,which starts from a specially designed U-shaped monomer with preinstalled NBN units at the zigzag edge.Chemical-bond-resolved non-contact atomic force microscopy(nc-AFM)imaging confirms the zigzag-terminated edges and the existence of NBN dopants.The electronic states distributed along the zigzag edges have been revealed after a silicon-layer intercalation at the interface of NBN-8-ZGNR and Au(111).Our work enriches the ZGNR family with a new dopant and larger width,which provides more candidates for future carbonbased nanoelectronic and spintronic applications.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11204201 and 11147142)the Natural Science Foundation for Young Scientists of Shanxi Province,China(Grant No.2013021010-1)
文摘The electric field effect in ultrathin zigzag graphene nanoribbons containing only three or four zigzag carbon chains is studied by first-principles calculations, and the change of conducting mechanism is observed with increasing in-plane electric field perpendicular to the ribbon. Wider zigzag graphene nanoribbons have been predicted to be spin-splitted for both valence band maximum（VBM） and conduction band minimum（CBM） with an applied electric field and become half-metal due to the vanishing band gap of one spin with increasing applied field. The change of VBM for the ultrathin zigzag graphene nanoribbons is similar to that for the wider ones when an electric field is applied. However, in the ultrathin zigzag graphene nanoribbons, there are two kinds of CBMs, one is spin-degenerate and the other is spin-splitted, and both are tunable by the electric field. Moreover, the two CBMs are spatially separated in momentum space. The conducting mechanism changes from spin-degenerate CBM to spin-splitted CBM with increasing applied electric field. Our results are confirmed by density functional calculations with both LDA and GGA functionals, in which the LDA always underestimates the band gap while the GGA normally produces a bigger band gap than the LDA.
基金The project is supported by Natural Science Foundation of Xinjiang(No.2017D01B36).
文摘Dioxin is a highly toxic and caustic substance,which widely existed in the atmosphere,soil and water with tiny particles.Dioxin pollution has become a major problem that concerns the survival of mankind,which must be strictly controlled.The bond length,bond angle,energy,dipole moment,orbital energy level distribution of dioxin under the external field are investigated using DFT(density functional theory)on basis set level of B3LYP/6-31G(d,p).The results indicate that with the increase of the electric field,the length of one Carbon-Oxygen bond increases while another Carbon-Oxygen bond decreases.The energy gradually decreases with the electric field,while the change of the dipole moment has an opposite trend.In the infrared spectra,the vibration frequency decreases with the electric field increasing and shows an obvious red shift.Moreover,the ultraviolet-visible absorption spectra under different electric fields are analyzed with TD-DFT(time-dependent density functional theory)method.The wavelength of the strongest absorption peak increases and occurs red shift with the increase of the electric field.All the above results can provide reference for further research on the properties of dioxin under different external electric field.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10774039)the Natural Science Foundation of Henan Province,China (Grant No. 092300410249)+1 种基金the Natural Science Foundation of the Education Bureau of Henan Province,China (Grant No. 2010A140008)the Foundation for University Young Core Instructors of Henan Province,China (Grant No. 2009GGJS-044)
文摘Geometry and vibrational frequencies of the ground state of Si2O2 molecule are studied using density function theory （DFT） at the level of cc-pvtz and 6-311-k＋G^＊＊. It is found that the optimizing value by B31yp/cc-pvtz is closer to the experimental data. The excited properties under different external electric fields are also investigated by the time-dependent-DFT method. Transitions from the ground state of Si2O2 molecule to the first singlet state under different external electric fields can take place more easily. The corresponding absorption spectral line is about 360 nm in wavelength and the excitation energy is about 3.4 eV.
基金supported by the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province(No.18KJA140002)National Natural Science Foundation of China(Nos.11564040,21763027)+1 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX18_1015)College Students’ Practice Innovation Training Program of Nuist(No.201810300033Z)
文摘Disulfur dichloride is a hazardous substance, which is irritating to the eyes. It is significant to study the physical and dissociation properties under external electric fields. The bond length, energy, dipole moment, orbital energy level distribution, infrared spectra and dissociation properties of disulfur dichloride molecule under different external fields are obtained by using the density functional theory at the B3LYP/6-311++G(d, p) basis set level. In addition, ultraviolet-visible absorption spectra of the molecule in different electric fields are studied with configuration interaction-single excitation(CIS)/6-311++G(d, p) method. According to the results, it has been found that as the electric field exerted along the positive direction of the z-axis increases, the two sulfur-chlorine(S-Cl) bond lengths become longer and tend to break, while the sulfur-sulfur(S-S) bond length becomes shorter and the energy gap decreases. The infrared spectrum and ultraviolet-visible absorption spectra both exhibit red shift under electric field. Moreover, by scanning the potential energy surface of disulfur dichloride about S-Cl bond, the dissociation barrier decreases with the increase of positive electric field. When the external electric field arrives at 0.040 atomic units, the barrier disappears, meaning the dissociation of disulfur dichloride. The present results offer an important reference to further study of disulfur dichloride.
基金This work was financially supported by the Innovation and Entrepreneurship Training Program for College Students(No.S202110500041)the National Natural Science Foundation of China(No.51771071).
文摘Although the performance of the self-standing electrode has been enhanced for aqueous zinc-ion batteries(AZIBs),it is necessary to explore and analyse the deep modification mechanism(especially interface effects).Herein,density functional theory(DFT)calculations are applied to investigate the high-performance cathode based on the VO_(2)/carbon cloth composites with heterostructures interface(H-VO_(2)@CC).The adsorption energy comparisons and electron structure analyses verify that HVO_(2)@CC has extra activated sites at the interface,enhanced electrical conductivity,and structural stability for achieving highperformance AZIBs due to the presence of built-in electric field at the interfaces.Accordingly,the designed self-standing HVO_(2)@CC cathode delivers higher rate capacity,longer-life cyclability,and faster electronic/ion transmission kinetics benefiting from the synergistic effects.The risks of active material shedding and dissolution during the dis/charge process of two cathodes were evaluated via ex-situ ultraviolet–visible(UV–vis)spectrum and inductively coupled plasma-atomic emission spectroscopy(ICP-AES)technique.Finally,this investigation also explores the charge storage mechanism of H-VO_(2)@CC through various exsitu and in-situ characterization techniques.This finding can shed light on the significant potential of heterostructures interface engineering in practical applications and provide a valuable direction for the development of cathode materials for AZIBs and other metal-ion batteries.
基金the National Key Basic Research Program，the National Natural Science Foundation of China，Chinese Academy of Sciences，the Fundamental Research Funds for the Central Universities, and USTCSCC
基金supported by the National"973"Program of China under Grant No.2007CB310405
文摘The autocorrelation function of electronic wave packet of hydrogen atom in a strong electric field below the zero-field ionization threshold is investigated in the formalism of semiclassical theory. It is found that the autocorrelation depends on the applied laser pulse significantly. In the case of narrow laser pulse, the reviving peaks in the autocorrelation can be attributed to the closed orbits of electrons, which are related to the classical dynamics of the system. But this correspondence is wiped out with increasing the laser width because of the interference among the adjacent reviving peaks.
基金supported by the National Natural Science Foundation of China(No.21203127)the Beijing Higher Education Young Elite Teacher Project(YETP1629)the Scientific Research Base Development Program of the Beijing Municipal Commission of Education
文摘Several bare zigzag phosphorene nanoribbons with odd number of atoms in the direction perpendicular to the extended line are investigated by using HSE06 density functional theory.These nanoribbons are as stable as those with even number of atoms.Primitive cells of the nanoribbons are metals,while edge self-passivation and distortion in the supercell structures cause metal-semiconductor transition.The band gaps of semiconducting nanoribbons are around 0.4 eV,which is enough for high on/off ratio in device operation.Compared to the conduction bands,the valence bands have smaller deformation potential constants and larger band width.Thus,the hole mobilities of the nanoribbons（10 cm^2·V^（-1）·s^（-1）） are one order higher than the electron mobilities.Bare zigzag phosphorene nanoribbons with odd number of atoms can also be candidates for small-size high-speed electronic devices.
基金This project was supported by the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province of China(No.18KJA140002)National Natural Science Foundation of China(Nos.11564040,21763027)+1 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX18_1015)Undergraduate Training Program for Innovation and Entrepreneurship(Nos.201710762008,201710762055)
文摘Oxalyl chloride is a highly toxic and caustic substance, which widely exists in human production and life as a kind of volatile organic compound. Based on the density functional theory B3 LYP at 6-311++G(d, p) level, the influences of external electric field on the bond length, bond energy, dipole moment and dissociation mechanism are optimized. The results indicate that the C_1–Cl_3 bond length increases while the C_4–Cl_6 bond decreases. At the same time, the carbon-carbon bond length gradually increases with the increase of electric field. The total energy decreases while the dipole moment gradually increases with the increase of electric field. In the infrared spectra, the vibration frequency of the carbon-chlorine(C_4–Cl_6) bond decreases while the vibration frequency of the carbon-oxygen bond increases. In the ultraviolet-visible spectra, the wavelength of the strongest absorption peak increases as the external electric field increases and shows an observable red shift phenomenon. Additionally, single point energies of oxalyl chloride along the carbon-carbon bond are scanned with the equation-of-motion coupled cluster method restricted to single and double excitations(EOM-CCSD) method and the potential energy curves under different external electric fields are obtained. The dissociation barrier in potential energy curve decreases because of the breakage of carbon-carbon bond with the increase of external electric field. These results provide reference for further researches on the properties of oxalyl chloride and offer a theoretical basis for the study of oxalyl chloride degradation.
基金supported by the Fund of University of Mazandaran,Iran
文摘The structural and electronic properties of a(4,0) zigzag single-walled carbon nanotube(SWCNT) under parallel and transverse electric fields with strengths of 0-1.4×10-2 a.u.were studied using the density functional theory(DFT) B3LYP/6-31G* method.Results show that the properties of the SWCNT are dependent on the external electric field.The applied external electric field strongly affects the molecular dipole moments.The induced dipole moments increase linearly with increase in the electrical field intensities.This study shows that the application of parallel and transverse electric fields results in changes in the occupied and virtual molecular orbitals(MOs) but the energy gap between the highest occupied MO(HOMO) and the lowest unoccupied MO(LUMO) of this SWCNT is less sensitive to the electric field strength.The electronic spatial extent(ESE) and length of the SWCNT show small changes over the entire range of the applied electric field strengths.The natural bond orbital(NBO) electric charges on the atoms of the SWCNT show that increase in the external electric field strength increases the separation of the center of the positive and negative electric charges of the carbon nanotube.
基金The work was supported by grants from the National Key Research and Development Program of China(No.2019YFA0308500)the National Natural Science Foundation of China(No.61888102)+5 种基金the Chinese Academy of Sciences(Nos.XDB30000000 and YSBR-003)the EU Graphene Flagship(Graphene Core 3,No.881603)the H2020-MSCA-ITN(ULTIMATE,No.813036)the Center for Advancing Electronics Dresden(CfAED)the H2020-EU.1.2.2.-FET Proactive Grant(LIGHT-CAP,No.101017821)the DFG-SNSF Joint Switzerland-German Research Project(EnhanTopo,No.429265950).
文摘Zigzag graphene nanoribbons(ZGNRs)with spin-polarized edge states have potential applications in carbon-based spintronics.The electronic structure of ZGNRs can be effectively tuned by different widths or dopants,which requires delicately designed monomers.Here,we report the successful synthesis of ZGNR with a width of eight carbon zigzag lines and nitrogen-boronnitrogen(NBN)motifs decorated along the zigzag edges(NBN-8-ZGNR)on Au(111)surface,which starts from a specially designed U-shaped monomer with preinstalled NBN units at the zigzag edge.Chemical-bond-resolved non-contact atomic force microscopy(nc-AFM)imaging confirms the zigzag-terminated edges and the existence of NBN dopants.The electronic states distributed along the zigzag edges have been revealed after a silicon-layer intercalation at the interface of NBN-8-ZGNR and Au(111).Our work enriches the ZGNR family with a new dopant and larger width,which provides more candidates for future carbonbased nanoelectronic and spintronic applications.
