Based on the combination of Racah＇s group-theoretical consideration with Slater＇s wavefunction, a 91 ×91 complete energy matrix is established in tetragonal ligand field D2d for Pr3＋ ion. Thus, the Stark energ...Based on the combination of Racah＇s group-theoretical consideration with Slater＇s wavefunction, a 91 ×91 complete energy matrix is established in tetragonal ligand field D2d for Pr3＋ ion. Thus, the Stark energy-levels of Pr3＋ ions doped separately in LiYF4 and LiBiF4 crystals are calculated, and our calculations imply that the complete energy matrix method can be used as an effective tool to calculate the energy-levels of the systems doped by rare earth ions. Besides, the influence of Pr3＋ on energy-level splitting is investigated, and the similarities and the differences between the two doped crystals are demonstrated in detail by comparing their several pairs of curves and crystal field strength quantities. We see that the energy splitting patterns are similar and the crystal field interaction of LiYF4：Pr3＋ is stronger than that of LiBiF4：Pr3＋.展开更多
We theoretically investigate the Autler–Townes（AT） splitting in the photoelectron spectrum of four-level ladder K2 molecule driven by a pump 1-pump 2-probe pulse via employing the time-dependent wave packet approac...We theoretically investigate the Autler–Townes（AT） splitting in the photoelectron spectrum of four-level ladder K2 molecule driven by a pump 1-pump 2-probe pulse via employing the time-dependent wave packet approach. The effects of the pump-1 laser intensity and wavelength on AT splitting are studied for the first time. The magnitude of AT splitting increases with increasing the pump-1 laser intensity. The triple splitting with asymmetric profile occurs due to the nonresonant excitation. The triple structure is transformed into a double structure（near-resonant region）, and then becomes a peak（far-off resonant region） progressively as the pump-1 laser is detuned from the resonance wavelength, which can be explained in terms of the asymmetric excitation/population of dressed states. The splitting between adjacent peaks and the splitting between the two sideband peaks in the triplet do not change with the pump-1 pulse wavelength. The three peaks shift toward lower energy with the same shift 1/4^＊△1 as the pump-1 wavelength changes in near-resonant region.The asymptotic behaviors of AT splitting with the pump-1 laser intensity are interesting in the threshold points of the near-resonant region and the far-off resonant region.展开更多
Perovskite material is one of the promising classes of redox catalysts for hydrogen production through two-step ther-mochemical H20 splitting.Herein,an analogue of La1-xCaxMnO3 perovskite was systematically investigat...Perovskite material is one of the promising classes of redox catalysts for hydrogen production through two-step ther-mochemical H20 splitting.Herein,an analogue of La1-xCaxMnO3 perovskite was systematically investigated as a catalyst for thermochemical H2 evolution.The Ca doping level（x = 0.2,0.4,0.6,0.8）and re-oxidation temperature were com-prehensively optimized for the improvement of catalytic performance.According to our experimental results,La0.6-Ca0.4MnO3 perovskite displayed the highest yield of H2 at the re-oxidation temperature of 900℃ and the obtained H2 production was -10 times higher than that of the benchmark ceria catalyst under the same experimental condition.More importantly,Lao.6Ca0.4MnO3 perovskite catalyst exhibited impressive cyclic stability in repetitive O2 and H2 test.展开更多
In lanthanide(Ln)complexes,the oversight of f-electrons and inner-shell relativistic interactions has constituted a critical gap,limiting a nuanced understanding and modulation of their luminescent properties.Addressi...In lanthanide(Ln)complexes,the oversight of f-electrons and inner-shell relativistic interactions has constituted a critical gap,limiting a nuanced understanding and modulation of their luminescent properties.Addressing this issue,our study introduces a pioneering series of Ln-based metal-organic frameworks(Ln-MOFs),designated as Ln-TCPP,utilizing tetraphenylpyrazinederived ligand and Ln^(3+)ions(Ln=Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb and Lu)to modulate luminescence through advanced synthesis and theoretical analysis.We particularly emphasize the enhancement of Eu^(3+)luminescence in Ln-TCPP,where incorporating Ag^(+)ions to replace[(CH_(3))_(2)NH_(2)]^(+)within the Ln-MOFs plays a pivotal role.Theoretically,by employing timedependent density functional theory(TD-DFT)with full-electron relativistic effects,we demonstrate that Ag^(+)ions induce a splitting in the energy levels of Eu^(3+).This splitting effectively reduces the rate of non-radiative transitions,significantly amplifying Eu^(3+)emission intensity.Our findings not only fill a long-standing void in understanding the all-electron relativistic interaction between f-electrons in Ln-MOFs luminescence but also establish a new strategy for controlling and optimizing the luminescent efficacy of these materials for potential applications.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10774103 and 10974138)
文摘Based on the combination of Racah＇s group-theoretical consideration with Slater＇s wavefunction, a 91 ×91 complete energy matrix is established in tetragonal ligand field D2d for Pr3＋ ion. Thus, the Stark energy-levels of Pr3＋ ions doped separately in LiYF4 and LiBiF4 crystals are calculated, and our calculations imply that the complete energy matrix method can be used as an effective tool to calculate the energy-levels of the systems doped by rare earth ions. Besides, the influence of Pr3＋ on energy-level splitting is investigated, and the similarities and the differences between the two doped crystals are demonstrated in detail by comparing their several pairs of curves and crystal field strength quantities. We see that the energy splitting patterns are similar and the crystal field interaction of LiYF4：Pr3＋ is stronger than that of LiBiF4：Pr3＋.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.41104094 and 11174119)the Research Fund for the Doctoral Program of Higher Education of China(Grant No.20114324120002)+1 种基金the Research Foundation of Education Bureau of Hunan Province,China(Grant No.12C0370)the Scientific Research Foundation for the Returned Overseas Chinese Scholars
文摘We theoretically investigate the Autler–Townes（AT） splitting in the photoelectron spectrum of four-level ladder K2 molecule driven by a pump 1-pump 2-probe pulse via employing the time-dependent wave packet approach. The effects of the pump-1 laser intensity and wavelength on AT splitting are studied for the first time. The magnitude of AT splitting increases with increasing the pump-1 laser intensity. The triple splitting with asymmetric profile occurs due to the nonresonant excitation. The triple structure is transformed into a double structure（near-resonant region）, and then becomes a peak（far-off resonant region） progressively as the pump-1 laser is detuned from the resonance wavelength, which can be explained in terms of the asymmetric excitation/population of dressed states. The splitting between adjacent peaks and the splitting between the two sideband peaks in the triplet do not change with the pump-1 pulse wavelength. The three peaks shift toward lower energy with the same shift 1/4^＊△1 as the pump-1 wavelength changes in near-resonant region.The asymptotic behaviors of AT splitting with the pump-1 laser intensity are interesting in the threshold points of the near-resonant region and the far-off resonant region.
基金financially supported by Australian Research Council(ARC)the National Natural Science Foundation of China(Grant Nos.51372248 and 51432009)
文摘Perovskite material is one of the promising classes of redox catalysts for hydrogen production through two-step ther-mochemical H20 splitting.Herein,an analogue of La1-xCaxMnO3 perovskite was systematically investigated as a catalyst for thermochemical H2 evolution.The Ca doping level（x = 0.2,0.4,0.6,0.8）and re-oxidation temperature were com-prehensively optimized for the improvement of catalytic performance.According to our experimental results,La0.6-Ca0.4MnO3 perovskite displayed the highest yield of H2 at the re-oxidation temperature of 900℃ and the obtained H2 production was -10 times higher than that of the benchmark ceria catalyst under the same experimental condition.More importantly,Lao.6Ca0.4MnO3 perovskite catalyst exhibited impressive cyclic stability in repetitive O2 and H2 test.
基金supported by the National Natural Science Foundation of China (22221001,22131007,22401119)the Science and Technology Major Plan of Gansu Province (23ZDGA012,24JRRA435)+1 种基金the 111 Project (B20027)the Fundamental Research Funds for the Central Universities (lzujbky-2024-jdzx13)。
文摘In lanthanide(Ln)complexes,the oversight of f-electrons and inner-shell relativistic interactions has constituted a critical gap,limiting a nuanced understanding and modulation of their luminescent properties.Addressing this issue,our study introduces a pioneering series of Ln-based metal-organic frameworks(Ln-MOFs),designated as Ln-TCPP,utilizing tetraphenylpyrazinederived ligand and Ln^(3+)ions(Ln=Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb and Lu)to modulate luminescence through advanced synthesis and theoretical analysis.We particularly emphasize the enhancement of Eu^(3+)luminescence in Ln-TCPP,where incorporating Ag^(+)ions to replace[(CH_(3))_(2)NH_(2)]^(+)within the Ln-MOFs plays a pivotal role.Theoretically,by employing timedependent density functional theory(TD-DFT)with full-electron relativistic effects,we demonstrate that Ag^(+)ions induce a splitting in the energy levels of Eu^(3+).This splitting effectively reduces the rate of non-radiative transitions,significantly amplifying Eu^(3+)emission intensity.Our findings not only fill a long-standing void in understanding the all-electron relativistic interaction between f-electrons in Ln-MOFs luminescence but also establish a new strategy for controlling and optimizing the luminescent efficacy of these materials for potential applications.
