Traditional ligand-field theory has to be improved by taking into account both 'pure electronic' contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy). By means of ...Traditional ligand-field theory has to be improved by taking into account both 'pure electronic' contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy). By means of improved ligand-field theory, R1, R2, R'3, R'2, and R'1 lines, U band, ground-state zero-field-splitting (GSZFS), and ground-state g factors of ruby and/or GSGG: Cr3+ as well as thermal shifts of GSZFS, R1 line and R2 line of ruby have been calculated.The results are in very good agreement with the experimental data. Moreover, it is found that the value of cubic-field parameter given by traditional ligand-field theory is inappropriately large. For thermal shifts of GSZFS, R1 line and R2 line of ruby, several conclusions have also been obtained.展开更多
With the values of parameters obtained from improved ligand-field theory,by taking into account all theirreducible representations and their components in EPI as well as all the levels and the admixtures of basic wave...With the values of parameters obtained from improved ligand-field theory,by taking into account all theirreducible representations and their components in EPI as well as all the levels and the admixtures of basic wavefunc-tions within d^3 electronic configuration,the R-line thermal broadenings(TB)of both MgO:Cr^(3+)and MgO:V^(2+)havemicroscopic-theoretically been calculated.The results are in very good agreement with the experimental data.It is foundthat the R-line TB of MgO:Cr^(3+)or MgO:V^(2+)comes from the first-order term of EPI.The elastic Raman scattering ofacoustic phonons plays a dominant role in R-line TB of MgO:Cr^(3+)or MgO:V^(2+).展开更多
By means of an improved ligand-field theory,the'pure electronic' PS and the PS due to EPI of R line ofMgO:V^(2+) have been calculated,respectively.The calculated results are in very good agreement with the exp...By means of an improved ligand-field theory,the'pure electronic' PS and the PS due to EPI of R line ofMgO:V^(2+) have been calculated,respectively.The calculated results are in very good agreement with the experimentaldata.The behaviors of the pure electronic PS of R line of MgO:V^(2+) and the PS of its R line due to EPI are different.Itis the combined effect of them that gives rise to the total PS of R line,which has satisfactorily explained the experimentalresults.The mixing-degree of [t_2~2(~3T_1)e ~4T_2〉and [t_3~2 ~2E〉 in the wavefunction of R level and its variation with pressurehave been calculated and analyzed.The comparison between the feature of R-line PS of MgO:V^(2+) and that of MgO:Cr^(3+)has been made.展开更多
By extending the usual DV-X<sub>α</sub> calculation and applying Bird’s ligand-field theory, wepresent a theoretical method for calculating d-d ligand-field spectra of transition-metal com-plexes. Compar...By extending the usual DV-X<sub>α</sub> calculation and applying Bird’s ligand-field theory, wepresent a theoretical method for calculating d-d ligand-field spectra of transition-metal com-plexes. Comparison between the calculated d-d ligand-field spectrum and the experimental （orother theoretical） results of cluster （CrF<sub>6</sub>）<sup>3-</sup> shows that this method is convenient and ef-fective.展开更多
Protecting clusters from coalescing by ligands has been universally adopted in the chemical synthesis of atomically precise clusters.Apart from the stabilization role,the effect of ligands on the electronic properties...Protecting clusters from coalescing by ligands has been universally adopted in the chemical synthesis of atomically precise clusters.Apart from the stabilization role,the effect of ligands on the electronic properties of cluster cores in constructing superatoms,however,has not been well understood.In this letter,a comprehensive theoretical study about the effect of an organic ligand,methylated N-heterocyclic carbene(C_(5)N_(2)H_(8)),on the geometrical and electronic properties of the aluminum-based clusters XAl_(12)(X=Al,C and P)featuring different valence electron shells was conducted by utilizing the density functional theory(DFT)calculations.It was observed that the ligand can dramatically alter the electronic properties of these aluminum-based clusters while maintaining their structural stability.More intriguingly,different from classical superatom design strategies,the proposed ligation strategy was evidenced to possess the capability of remarkably reducing the ionization potentials(IP)of these clusters forming the ligated superalkalis,which is regardless of their shell occupancy.The charge transfer complex formed during the ligation process,which regulates the electronic spectrum through the electrostatic Coulomb potential,was suggested to be responsible for such an IP drop.The ligation strategy highlighted here may provide promising opportunities in realizing the superatom synthesis in the liquid phase.展开更多
文摘Traditional ligand-field theory has to be improved by taking into account both 'pure electronic' contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy). By means of improved ligand-field theory, R1, R2, R'3, R'2, and R'1 lines, U band, ground-state zero-field-splitting (GSZFS), and ground-state g factors of ruby and/or GSGG: Cr3+ as well as thermal shifts of GSZFS, R1 line and R2 line of ruby have been calculated.The results are in very good agreement with the experimental data. Moreover, it is found that the value of cubic-field parameter given by traditional ligand-field theory is inappropriately large. For thermal shifts of GSZFS, R1 line and R2 line of ruby, several conclusions have also been obtained.
基金supported partially by National Natural Science Foundation of China under Grant No.40841012
文摘With the values of parameters obtained from improved ligand-field theory,by taking into account all theirreducible representations and their components in EPI as well as all the levels and the admixtures of basic wavefunc-tions within d^3 electronic configuration,the R-line thermal broadenings(TB)of both MgO:Cr^(3+)and MgO:V^(2+)havemicroscopic-theoretically been calculated.The results are in very good agreement with the experimental data.It is foundthat the R-line TB of MgO:Cr^(3+)or MgO:V^(2+)comes from the first-order term of EPI.The elastic Raman scattering ofacoustic phonons plays a dominant role in R-line TB of MgO:Cr^(3+)or MgO:V^(2+).
文摘By means of an improved ligand-field theory,the'pure electronic' PS and the PS due to EPI of R line ofMgO:V^(2+) have been calculated,respectively.The calculated results are in very good agreement with the experimentaldata.The behaviors of the pure electronic PS of R line of MgO:V^(2+) and the PS of its R line due to EPI are different.Itis the combined effect of them that gives rise to the total PS of R line,which has satisfactorily explained the experimentalresults.The mixing-degree of [t_2~2(~3T_1)e ~4T_2〉and [t_3~2 ~2E〉 in the wavefunction of R level and its variation with pressurehave been calculated and analyzed.The comparison between the feature of R-line PS of MgO:V^(2+) and that of MgO:Cr^(3+)has been made.
基金Project supported by the National Natural Science Foundation of China.
文摘By extending the usual DV-X<sub>α</sub> calculation and applying Bird’s ligand-field theory, wepresent a theoretical method for calculating d-d ligand-field spectra of transition-metal com-plexes. Comparison between the calculated d-d ligand-field spectrum and the experimental （orother theoretical） results of cluster （CrF<sub>6</sub>）<sup>3-</sup> shows that this method is convenient and ef-fective.
基金supported by the Innovation Project of Jinan Science and Technology Bureau(No.2021GXRC032)the Taishan Scholars Project of Shandong Province(No.ts201712011)+4 种基金the National Natural Science Foundation of China(NSFC,Nos.92161101,21603119)the Natural Science Foundation of Shandong Province(No.ZR2020ZD35)the Shandong University Multidisciplinary Research and Innovation Team of Young Scholars(No.2020QNQT015)the Young Scholars Program of Shandong University(YSPSDU,No.2018WLJH48)the Fundamental Research Funds of Shandong University(No.2017TB003).
文摘Protecting clusters from coalescing by ligands has been universally adopted in the chemical synthesis of atomically precise clusters.Apart from the stabilization role,the effect of ligands on the electronic properties of cluster cores in constructing superatoms,however,has not been well understood.In this letter,a comprehensive theoretical study about the effect of an organic ligand,methylated N-heterocyclic carbene(C_(5)N_(2)H_(8)),on the geometrical and electronic properties of the aluminum-based clusters XAl_(12)(X=Al,C and P)featuring different valence electron shells was conducted by utilizing the density functional theory(DFT)calculations.It was observed that the ligand can dramatically alter the electronic properties of these aluminum-based clusters while maintaining their structural stability.More intriguingly,different from classical superatom design strategies,the proposed ligation strategy was evidenced to possess the capability of remarkably reducing the ionization potentials(IP)of these clusters forming the ligated superalkalis,which is regardless of their shell occupancy.The charge transfer complex formed during the ligation process,which regulates the electronic spectrum through the electrostatic Coulomb potential,was suggested to be responsible for such an IP drop.The ligation strategy highlighted here may provide promising opportunities in realizing the superatom synthesis in the liquid phase.
