A new ratiometric Boltzmann thermometry approach is presented for the narrow-line red-emitting bright phosphor Al_(0.993)Cr_(0.007)B_(4O6)N.It relies on thermalization between the two excited states^(2)E_(g)(^(2)G)and...A new ratiometric Boltzmann thermometry approach is presented for the narrow-line red-emitting bright phosphor Al_(0.993)Cr_(0.007)B_(4O6)N.It relies on thermalization between the two excited states^(2)E_(g)(^(2)G)and^(2)T_(1g)(^(2)G)of Cr^(3+)with an energy gap of 620 cm^(−1)for optimized thermometry at room temperature.It is shown that nonradiative coupling between these excited states is very fast,with rates in the order of severalµs^(−1).Due to the comparably slow radiative decay(k_(r)=0.033 ms^(−1))of the lowest excited^(2)E_(g)(^(2)G)state,the dynamic working range of this Boltzmann thermometer for the deep red spectral range is exceptionally wide,between<77 K and>873 K,even outperforming the classic workhorse example of Er^(3+).At temperatures above 340 K,also spectrally well-resolved broad-band emission due to the spin-allowed^(4)T_(2g)(^(4)F)→^(4)A_(2g)(^(4)F)transition is detectable,which simultaneously offers a possibility of very sensitive(S_(r)(500 K)>2%K^(−1))ratiometric Boltzmann-type crossover thermometry for higher temperatures.These findings imply that Al_(0.993)Cr_(0.007)B_(4)O_(6)N is a particularly robust and bright red luminescent thermometer with a record-breaking dynamic working range for a luminescent transition metal ion.展开更多
The creation and propagation of longitudinal acoustic phonons （LAPs） in high quality hematite thin films （α-Fe203） epitaxially grown on different substrates （BaTiO3, SrTiO3, and LaAlO3） are investigated using t...The creation and propagation of longitudinal acoustic phonons （LAPs） in high quality hematite thin films （α-Fe203） epitaxially grown on different substrates （BaTiO3, SrTiO3, and LaAlO3） are investigated using the femtosecond pump- probe technique. Transient reflection measurements （AR/R） indicate the photo-excited electron dynamics, and the initial decay less than 1 ps and the slow decay of -500 ps are attributed to the electron-LO phonon coupling and electron-hole nonradiative recombination, respectively. LAPs in α-Fe2O3 film can be created by ultrafast excitation of the ligand field state, such as the ligand field transitions under 800-nm excitation as well as the ligand to metal charge-transfer with 400- nm excitation. The strain modulations of the sound velocity and the out-of-plane elastic properties are demonstrated in α-Fe2O3 film on different substrates.展开更多
Modulating the electronic structure has emerged as an effective strategy for optimizing the adsorption and catalytic capabilities of electrocatalysts in lithium-sulfur(Li-S)batteries.However,the regulation of electron...Modulating the electronic structure has emerged as an effective strategy for optimizing the adsorption and catalytic capabilities of electrocatalysts in lithium-sulfur(Li-S)batteries.However,the regulation of electronic structure involving spin-related charge transfer and orbital interactions has been largely underexplored in sulfur electrocatalysts.Herein,selenium-deficient bimetallic selenides embedded in a coaxial carbon layer(CoSe_(2-x)/ZnSe)were meticulously fabricated as electrocatalysts,aiming to modulate the electron spin state of Co catalytic sites to enhance the bidirectional lithium polysulfides(LiPSs)conversion kinetics and suppress the LiPSs shuttling effect.Density functional theory(DFT)calculations and experimental results indicate that the selenium vacancies at the CoSe_(2-x)/ZnSe heterointerfaces weaken the ligand fields and drive the Co 3d orbital electronic structure transition from low-spin to high-spin states.Such tailored spin state configuration generates more unpaired electrons and upshifts the dband center,thus accelerating the charge transfer and strengthening the orbital interactions between LiPSs and Co catalytic sites.As a consequence,the assembled Li-S batteries with CoSe_(2-x)/ZnSe electrocatalysts exhibit an ultralow average decay rate of 0.028%per cycle at 1 C over 1000 cycles.This work presents a novel strategy for manipulating ligand fields to realize electron spin state modulation in sulfur electrocatalysts.展开更多
Lanthanum-bearing iron lithium borate glass is a quaternary system for oxide glasses and was prepared via the melt-quenching method.The present article correlates the structure,optical,ligand field and M?ssbauer data ...Lanthanum-bearing iron lithium borate glass is a quaternary system for oxide glasses and was prepared via the melt-quenching method.The present article correlates the structure,optical,ligand field and M?ssbauer data on iron lithium borate glass co ntaining La^(3+).The density was measured,while the molar volume was calculated.Other physical parameters are well-described.With increasing the La_(2)O_(3) content within the glass network,infrared spectra analysis reveals structural modifications such as the increase in BO_(4) units and the decline in both BO_(3) units and NBO bonds content.Furthermore,optical absorption spectra were measured.The absorption spectra disclose a plethora of electronic transitions that are related to Fe^(3+)in tetrahedral and octahedral sites,however,Fe^(2+)phase is not observed in optical spectra,but it has a clear signature in M?ssbauer spectra.Besides,the glass absorption edges undergo a clear blue shift,reflecting an increased band gap energy(1.96-2.28 eV).The decline in NBO bonds justifies this trend.Bewitchingly,the values of crystal field splitting are increased,while the values of Racah parameters are decreased.This trend is justified by the decline in NBO bonds and increases electron localization around Fe cations.M?ssbauer spectra confirm the existence of Fe^(3+)in tetrahedral and octahedral sites,while Fe^(2+)exists in only a tetrahedral state.With increasing La_(2)O_(3) content,the isomer shift of Fe^(3+)in tetrahedral sites changes to be 0.312-0.329 mm/s,while the isomer shift of octahedral Fe^(3+)is 0.424-0.456 mm/s.These findings coincide with optical data.While the isomer shift of tetrahedral Fe^(2+)is 0.902-0.911 mm/s.Our results of structural,optical and ligand field associated with M?ssbauer spectra open more vistas toward the utility of these samples in the optics realm.展开更多
Electrochemical potential and ion diffusion of electrode materials restrain the energy and power densities of lithium-ion batteries,and these challenges also remain in the intercalation-type Li_(3)VO_(4)(LVO).In this ...Electrochemical potential and ion diffusion of electrode materials restrain the energy and power densities of lithium-ion batteries,and these challenges also remain in the intercalation-type Li_(3)VO_(4)(LVO).In this work,the local[VO_(4)]coordination symmetry in LVO is broken by a higher concentration of oxygen vacancies(Vö),resulting in an increased average V–O bond length and a larger ligand field splitting.These alterations reduce the energy level of the lowest unoccupied orbitals(e^(*))and lift the electrochemical potential,resulting in a higher voltage output.Additionally,the broken local symmetry in Vö-LVO is found to reduce the band gap and expand the ion transport channels,which favors enhancing electronic conductivity and facilitates ion diffusion,thereby improving the electrochemical kinetics in the energy storage process.The local symmetry broken sample(Vö-LVO)achieves a significantly improved capacity of 532 mAh/g at 0.1 A/g in comparison with 394 mAh/g of pristine LVO,and long cycling stability with retained capacity of 398 mAh/g at 1 A/g over 500 cycles compared with 236 mAh/g of the pristine LVO.The fundamental understanding paves the way to exploit high-performance electrodes via ligand field engineering for next-generation rechargeable batteries.展开更多
The photoelectron imagings of LaO-, CeO-, PRO-, and NdO- at 1064 nm are reported. The well resolved photoelectron spectra allow the electron affinities to be determined as 0.99（1） eV for LaO, 1.00（1） eV for CeO, 1...The photoelectron imagings of LaO-, CeO-, PRO-, and NdO- at 1064 nm are reported. The well resolved photoelectron spectra allow the electron affinities to be determined as 0.99（1） eV for LaO, 1.00（1） eV for CeO, 1.00（1） eV for PrO, and 1.01（1） eV for NdO, respectively. Density functional calculations and natural atomic orbital analyses show that the 4f electrons tend to be localized and suffer little from the charge states of the molecules. The photodetached electron mainly originates from the 6s orbital of the metals. The ligand field theory with the δ=2 assumption is still an effective method to analyze the ground states of the neutral and anionic lanthanide monoxides.展开更多
In this work, the magnetocrystalline anisotropy energy(MAE) on the surface of FeCoalloy film is extracted from x-ray magnetic linear dichroism(XMLD) experiments. The result indicates that the surface MAE value is nega...In this work, the magnetocrystalline anisotropy energy(MAE) on the surface of FeCoalloy film is extracted from x-ray magnetic linear dichroism(XMLD) experiments. The result indicates that the surface MAE value is negatively correlated with thickness. Through spectrum calculations and analysis, we find that besides the thickness effect, another principal possible cause may be the shape anisotropy resulting from the presence of interface roughness. These two factors lead to different electron structures on the fermi surface with different exchange fields, which produces different spin–orbit interaction anisotropies.展开更多
Based on density functional theory,first-principles calculation is applied to study the electronic properties of undoped and Ag-doped Zn O-Σ7(123^-0)twin grain boundaries(GBs).The calculated result indicates that the...Based on density functional theory,first-principles calculation is applied to study the electronic properties of undoped and Ag-doped Zn O-Σ7(123^-0)twin grain boundaries(GBs).The calculated result indicates that the twin GBs can facilitate the formation and aggregation of Ag substitution at Zn sites(AgZn)due to the strain release.Meanwhile,some twin GBs can also lower the ionization energy of AgZn.The density of state shows that the O–O bonds in GBs play a key role in the formation of a shallow acceptor energy level.When AgZnbonds with one O atom in the O–O bond,the antibonding state of the O–O bond becomes partially occupied.As a result,a weak spin splitting occurs in the antibonding state,which causes a shallow empty energy level above the valence band maximum.Further,the model can be applied to explain the origin of p-type conductivity in Ag-doped Zn O.展开更多
The electro optical characteristics of SrS∶Ce and SrGa 2S 4∶Ce as two kinds of hopeful blue TFEL phosphors have been intensively investigated. The color purity of SrGa 2S 4∶Ce is better than that of SrS∶Ce. ...The electro optical characteristics of SrS∶Ce and SrGa 2S 4∶Ce as two kinds of hopeful blue TFEL phosphors have been intensively investigated. The color purity of SrGa 2S 4∶Ce is better than that of SrS∶Ce. In this paper, the influence of Ga 3+ on photoluminescence (PL) characteristics of Ce 3+ is first reported. Ga 2S 3 was doped into SrS, then sintered. The emission spectra shift obviously towards short wavelength range with increase of Ga 3+ concentration. At the same time, the relative intensity of the excitation peaks corresponding to the interband absorption of SrS reduces, and the excitation efficiency corresponding to the transition from the ground state to the excited state of Ce 3+ ion increases. The ligand field around Ce 3+ is changed by doped Ga 3+ . The ionicity of the substituted become stronger and Ce 3+ -Ce 3+ interaction become weaker. These are favorite to blue emission.展开更多
The spin-polarized generalized gradient approximation（GGA）＋U approach was employed to study the bonding characteristics and magnetic coupling interactions in room-temperature phase α＇-NaV2O5. The calculated resui...The spin-polarized generalized gradient approximation（GGA）＋U approach was employed to study the bonding characteristics and magnetic coupling interactions in room-temperature phase α＇-NaV2O5. The calculated resuits indicate that the Vdry orbital is split off from other 3d orbitals in the VO5 pyramidal ligand field. The Vdry orbitals are hybridized strongly with the Opx/py orbitals, forming a V--O--V π bond in the ab plane. The ligand field effect together with the intra-atomic exchange splitting results in the insulating behavior. With the aid of Noodleman＇s bro- ken symmetry methods, the magnetic exchange constant was derived from mapping the relative energies onto the Heisenberg model. The antiferromagnetic（AFM） exchange energy, d, along the chain was calculated to be -593 K in good agreement with the experimental data.展开更多
Heterometallic 3d-4f clusters represent a promising class of multifunctional molecular materials,driven by the synergistic interactions between d-and f-electrons.Incorporating chirality into these systems further expa...Heterometallic 3d-4f clusters represent a promising class of multifunctional molecular materials,driven by the synergistic interactions between d-and f-electrons.Incorporating chirality into these systems further expands their potential applications,particularly in chiroptical and magneto-optical technologies.Herein,we report the successful synthesis of chiral[Ln_(3)Co_(2)](Ln=Er and Y)clusters using binaphthol-based ligands.Single-crystal X-ray diffraction reveals the coexistence of two distinct Co^(2+)coordination geometries:six-coordinate octahedron and five-coordinate trigonal bipyramid.Spectroscopic analyses demonstrate geometry-dependent chiroptical behavior:pentacoordinate Co^(2+)ions predominantly contribute to the circular dichroism(CD)features,while both geometries exhibit distinguishable signals in the magnetic circular dichroism(MCD)spectra.Notably,a pronounced magnetic dipole transition(^(4)I_(15/2)→^(4)I_(13/2))from Er^(3+)centers is observed in the near-infrared MCD region,displaying a high g-factor of 0.0078 T-1.This work highlights the configuration-and ligand field-dependent chiroptical responses in 3d-4f systems,providing new insights for the rational design of advanced magneto-optical devices.展开更多
基金support by the“Young College”of the North-Rhine Westphalian Academy of Science,Humanities,and the Arts.Generous funding by the German National Science Foundation(DFG,SU 1156/5-1,project no.554302036)and the Strategic Research Fund of the HHU Düsseldorf is also gratefully acknowledged.
文摘A new ratiometric Boltzmann thermometry approach is presented for the narrow-line red-emitting bright phosphor Al_(0.993)Cr_(0.007)B_(4O6)N.It relies on thermalization between the two excited states^(2)E_(g)(^(2)G)and^(2)T_(1g)(^(2)G)of Cr^(3+)with an energy gap of 620 cm^(−1)for optimized thermometry at room temperature.It is shown that nonradiative coupling between these excited states is very fast,with rates in the order of severalµs^(−1).Due to the comparably slow radiative decay(k_(r)=0.033 ms^(−1))of the lowest excited^(2)E_(g)(^(2)G)state,the dynamic working range of this Boltzmann thermometer for the deep red spectral range is exceptionally wide,between<77 K and>873 K,even outperforming the classic workhorse example of Er^(3+).At temperatures above 340 K,also spectrally well-resolved broad-band emission due to the spin-allowed^(4)T_(2g)(^(4)F)→^(4)A_(2g)(^(4)F)transition is detectable,which simultaneously offers a possibility of very sensitive(S_(r)(500 K)>2%K^(−1))ratiometric Boltzmann-type crossover thermometry for higher temperatures.These findings imply that Al_(0.993)Cr_(0.007)B_(4)O_(6)N is a particularly robust and bright red luminescent thermometer with a record-breaking dynamic working range for a luminescent transition metal ion.
基金Project supported by the National Natural Science Foundation of China(Grant No.11174195)
文摘The creation and propagation of longitudinal acoustic phonons （LAPs） in high quality hematite thin films （α-Fe203） epitaxially grown on different substrates （BaTiO3, SrTiO3, and LaAlO3） are investigated using the femtosecond pump- probe technique. Transient reflection measurements （AR/R） indicate the photo-excited electron dynamics, and the initial decay less than 1 ps and the slow decay of -500 ps are attributed to the electron-LO phonon coupling and electron-hole nonradiative recombination, respectively. LAPs in α-Fe2O3 film can be created by ultrafast excitation of the ligand field state, such as the ligand field transitions under 800-nm excitation as well as the ligand to metal charge-transfer with 400- nm excitation. The strain modulations of the sound velocity and the out-of-plane elastic properties are demonstrated in α-Fe2O3 film on different substrates.
基金supported by the National Natural Science Foundation of China(No.52172214,52472220)。
文摘Modulating the electronic structure has emerged as an effective strategy for optimizing the adsorption and catalytic capabilities of electrocatalysts in lithium-sulfur(Li-S)batteries.However,the regulation of electronic structure involving spin-related charge transfer and orbital interactions has been largely underexplored in sulfur electrocatalysts.Herein,selenium-deficient bimetallic selenides embedded in a coaxial carbon layer(CoSe_(2-x)/ZnSe)were meticulously fabricated as electrocatalysts,aiming to modulate the electron spin state of Co catalytic sites to enhance the bidirectional lithium polysulfides(LiPSs)conversion kinetics and suppress the LiPSs shuttling effect.Density functional theory(DFT)calculations and experimental results indicate that the selenium vacancies at the CoSe_(2-x)/ZnSe heterointerfaces weaken the ligand fields and drive the Co 3d orbital electronic structure transition from low-spin to high-spin states.Such tailored spin state configuration generates more unpaired electrons and upshifts the dband center,thus accelerating the charge transfer and strengthening the orbital interactions between LiPSs and Co catalytic sites.As a consequence,the assembled Li-S batteries with CoSe_(2-x)/ZnSe electrocatalysts exhibit an ultralow average decay rate of 0.028%per cycle at 1 C over 1000 cycles.This work presents a novel strategy for manipulating ligand fields to realize electron spin state modulation in sulfur electrocatalysts.
文摘Lanthanum-bearing iron lithium borate glass is a quaternary system for oxide glasses and was prepared via the melt-quenching method.The present article correlates the structure,optical,ligand field and M?ssbauer data on iron lithium borate glass co ntaining La^(3+).The density was measured,while the molar volume was calculated.Other physical parameters are well-described.With increasing the La_(2)O_(3) content within the glass network,infrared spectra analysis reveals structural modifications such as the increase in BO_(4) units and the decline in both BO_(3) units and NBO bonds content.Furthermore,optical absorption spectra were measured.The absorption spectra disclose a plethora of electronic transitions that are related to Fe^(3+)in tetrahedral and octahedral sites,however,Fe^(2+)phase is not observed in optical spectra,but it has a clear signature in M?ssbauer spectra.Besides,the glass absorption edges undergo a clear blue shift,reflecting an increased band gap energy(1.96-2.28 eV).The decline in NBO bonds justifies this trend.Bewitchingly,the values of crystal field splitting are increased,while the values of Racah parameters are decreased.This trend is justified by the decline in NBO bonds and increases electron localization around Fe cations.M?ssbauer spectra confirm the existence of Fe^(3+)in tetrahedral and octahedral sites,while Fe^(2+)exists in only a tetrahedral state.With increasing La_(2)O_(3) content,the isomer shift of Fe^(3+)in tetrahedral sites changes to be 0.312-0.329 mm/s,while the isomer shift of octahedral Fe^(3+)is 0.424-0.456 mm/s.These findings coincide with optical data.While the isomer shift of tetrahedral Fe^(2+)is 0.902-0.911 mm/s.Our results of structural,optical and ligand field associated with M?ssbauer spectra open more vistas toward the utility of these samples in the optics realm.
基金financially supported by the Natural Science Foundation of Fujian Province(2022J011269)the National Natural Science Foundation of China(52102277,52472238,52302193)+1 种基金the Fujian Provincial Key Laboratory of Functional Materials and Applications(fma2022005)the Fundamental Research Funds for the Central Universities,conducted by Tongji University。
文摘Electrochemical potential and ion diffusion of electrode materials restrain the energy and power densities of lithium-ion batteries,and these challenges also remain in the intercalation-type Li_(3)VO_(4)(LVO).In this work,the local[VO_(4)]coordination symmetry in LVO is broken by a higher concentration of oxygen vacancies(Vö),resulting in an increased average V–O bond length and a larger ligand field splitting.These alterations reduce the energy level of the lowest unoccupied orbitals(e^(*))and lift the electrochemical potential,resulting in a higher voltage output.Additionally,the broken local symmetry in Vö-LVO is found to reduce the band gap and expand the ion transport channels,which favors enhancing electronic conductivity and facilitates ion diffusion,thereby improving the electrochemical kinetics in the energy storage process.The local symmetry broken sample(Vö-LVO)achieves a significantly improved capacity of 532 mAh/g at 0.1 A/g in comparison with 394 mAh/g of pristine LVO,and long cycling stability with retained capacity of 398 mAh/g at 1 A/g over 500 cycles compared with 236 mAh/g of the pristine LVO.The fundamental understanding paves the way to exploit high-performance electrodes via ligand field engineering for next-generation rechargeable batteries.
基金This work was supported by the National Natural Science Foundation of China （No.20933003） and the National Basic Research Program of China （No.2010CB732306）.
文摘The photoelectron imagings of LaO-, CeO-, PRO-, and NdO- at 1064 nm are reported. The well resolved photoelectron spectra allow the electron affinities to be determined as 0.99（1） eV for LaO, 1.00（1） eV for CeO, 1.00（1） eV for PrO, and 1.01（1） eV for NdO, respectively. Density functional calculations and natural atomic orbital analyses show that the 4f electrons tend to be localized and suffer little from the charge states of the molecules. The photodetached electron mainly originates from the 6s orbital of the metals. The ligand field theory with the δ=2 assumption is still an effective method to analyze the ground states of the neutral and anionic lanthanide monoxides.
基金supported by the National Natural Science Foundation of China(Grant Nos.11075176 and 11375131)
文摘In this work, the magnetocrystalline anisotropy energy(MAE) on the surface of FeCoalloy film is extracted from x-ray magnetic linear dichroism(XMLD) experiments. The result indicates that the surface MAE value is negatively correlated with thickness. Through spectrum calculations and analysis, we find that besides the thickness effect, another principal possible cause may be the shape anisotropy resulting from the presence of interface roughness. These two factors lead to different electron structures on the fermi surface with different exchange fields, which produces different spin–orbit interaction anisotropies.
基金Project supported by the National Natural Science Foundation of China(Grant No.11364009)Natural Science Foundation of Guangxi Province,China(Grant No.2014GXNSFFA118004)
文摘Based on density functional theory,first-principles calculation is applied to study the electronic properties of undoped and Ag-doped Zn O-Σ7(123^-0)twin grain boundaries(GBs).The calculated result indicates that the twin GBs can facilitate the formation and aggregation of Ag substitution at Zn sites(AgZn)due to the strain release.Meanwhile,some twin GBs can also lower the ionization energy of AgZn.The density of state shows that the O–O bonds in GBs play a key role in the formation of a shallow acceptor energy level.When AgZnbonds with one O atom in the O–O bond,the antibonding state of the O–O bond becomes partially occupied.As a result,a weak spin splitting occurs in the antibonding state,which causes a shallow empty energy level above the valence band maximum.Further,the model can be applied to explain the origin of p-type conductivity in Ag-doped Zn O.
文摘The electro optical characteristics of SrS∶Ce and SrGa 2S 4∶Ce as two kinds of hopeful blue TFEL phosphors have been intensively investigated. The color purity of SrGa 2S 4∶Ce is better than that of SrS∶Ce. In this paper, the influence of Ga 3+ on photoluminescence (PL) characteristics of Ce 3+ is first reported. Ga 2S 3 was doped into SrS, then sintered. The emission spectra shift obviously towards short wavelength range with increase of Ga 3+ concentration. At the same time, the relative intensity of the excitation peaks corresponding to the interband absorption of SrS reduces, and the excitation efficiency corresponding to the transition from the ground state to the excited state of Ce 3+ ion increases. The ligand field around Ce 3+ is changed by doped Ga 3+ . The ionicity of the substituted become stronger and Ce 3+ -Ce 3+ interaction become weaker. These are favorite to blue emission.
基金Supported by the National Natural Science Foundation of China(No.50672031)the Program for Changjiang Scholar and Innovative Research Team in Universities of China(No.IRT0625)the Scientific and Technologic Research and Development Program of Jilin Province, China(No.20060511).
文摘The spin-polarized generalized gradient approximation（GGA）＋U approach was employed to study the bonding characteristics and magnetic coupling interactions in room-temperature phase α＇-NaV2O5. The calculated resuits indicate that the Vdry orbital is split off from other 3d orbitals in the VO5 pyramidal ligand field. The Vdry orbitals are hybridized strongly with the Opx/py orbitals, forming a V--O--V π bond in the ab plane. The ligand field effect together with the intra-atomic exchange splitting results in the insulating behavior. With the aid of Noodleman＇s bro- ken symmetry methods, the magnetic exchange constant was derived from mapping the relative energies onto the Heisenberg model. The antiferromagnetic（AFM） exchange energy, d, along the chain was calculated to be -593 K in good agreement with the experimental data.
基金supported by the National Natural Science Foundation of China(Nos.92461305,92161203 and 92361301).
文摘Heterometallic 3d-4f clusters represent a promising class of multifunctional molecular materials,driven by the synergistic interactions between d-and f-electrons.Incorporating chirality into these systems further expands their potential applications,particularly in chiroptical and magneto-optical technologies.Herein,we report the successful synthesis of chiral[Ln_(3)Co_(2)](Ln=Er and Y)clusters using binaphthol-based ligands.Single-crystal X-ray diffraction reveals the coexistence of two distinct Co^(2+)coordination geometries:six-coordinate octahedron and five-coordinate trigonal bipyramid.Spectroscopic analyses demonstrate geometry-dependent chiroptical behavior:pentacoordinate Co^(2+)ions predominantly contribute to the circular dichroism(CD)features,while both geometries exhibit distinguishable signals in the magnetic circular dichroism(MCD)spectra.Notably,a pronounced magnetic dipole transition(^(4)I_(15/2)→^(4)I_(13/2))from Er^(3+)centers is observed in the near-infrared MCD region,displaying a high g-factor of 0.0078 T-1.This work highlights the configuration-and ligand field-dependent chiroptical responses in 3d-4f systems,providing new insights for the rational design of advanced magneto-optical devices.
