We investigate Autler-Townes splitting in the photoelectron spectra of K2 molecule driven by pump-probe pulses via employing the time-dependent wave packet approach. It is found that the magnitude of Aulter-Townes spl...We investigate Autler-Townes splitting in the photoelectron spectra of K2 molecule driven by pump-probe pulses via employing the time-dependent wave packet approach. It is found that the magnitude of Aulter-Townes splitting varies with the wavelength of the intense laser pulse. In particular, the phenomenon of Aulter-Townes splitting vanishes for the far-off resonance of the pump pulse. Also, the split peaks of Autler Townes in the case of resonant pump pulse give us an approach to directly obtaining the transition dipole moment of a molecule.展开更多
Wave packet dynamics of the Li2 molecule are investigated by using the time-dependent quantum wave packet method, and the time-resolved photoelectron spectra of the Li2 molecule are calculated. The time-resolved wave ...Wave packet dynamics of the Li2 molecule are investigated by using the time-dependent quantum wave packet method, and the time-resolved photoelectron spectra of the Li2 molecule are calculated. The time-resolved wave packet theory is used to reasonably interpret the phenomena of the photoelectron spectra for different parameters. Our calculation shows that the loss of the wave packets in the shelf state area of E1∑g＋ plays a prominent role in the process of photoionization with the increase of the delay time. Moreover, the oscillation of the wave packet on the E1∑g＋ curve symbolizes a decreasing process of energy.展开更多
We report our numerical simulation on the dynamic interference photoelectron spectra for a one-dimensional （1D） He model exposed to intense ultrashort extreme ultraviolet （XUV） laser pulses. The results demonstrat...We report our numerical simulation on the dynamic interference photoelectron spectra for a one-dimensional （1D） He model exposed to intense ultrashort extreme ultraviolet （XUV） laser pulses. The results demonstrate an unambiguous interference feature in the photoelectron spectra, and the interference is unveiled to originate from the dynamic Stark effect. The interference photoelectron spectra are prompted for intense sub-femtosecond XUV laser pulses in double ionization. The stationary phase picture is corroborated qualitatively in the two-electron system. The ability of probing the dynamic Stark effect by the photoelectron spectra in a pragmatic experiment of single-photon double ionization of He may shed light on further investigation on multi-electron atoms and molecules.展开更多
The energy band structure with type-I alignment at the PbTe/CdTe（111） heterojunction interface is determined by the ultraviolet photoelectron spectrum using synchrotron radiation. The valence band and conduction ban...The energy band structure with type-I alignment at the PbTe/CdTe（111） heterojunction interface is determined by the ultraviolet photoelectron spectrum using synchrotron radiation. The valence band and conduction band offsets are obtained to be 0.09±0.12 and 1.19±0.12 eV, respectively. These results are in agreement with theoretically predicted ones. The accurate determination of the valence band and conduction band offsets is useful for the fundamental understanding of the mid-infrared light emission from the PbTe/CdTe heterostructures and its application in devices.展开更多
The through--space and through--bond interactions in 1, 5 -- Cyclooctadiyne are studied. It is shown, with the assistance of improved MS--X_α method, that the through- space interactions decrease with the distance of...The through--space and through--bond interactions in 1, 5 -- Cyclooctadiyne are studied. It is shown, with the assistance of improved MS--X_α method, that the through- space interactions decrease with the distance of the orbitals, and both through--space and through--bond interactions of 1, 5- Cyclooctadiyne are sizable but those two interactions oppose each other causing the net splitting to be small for π_z orbital. The calculated ionization potentials are in good agreement with the experiment of photoelectron spectra.展开更多
Based on numerical solutions of the time-dependent Schr ¨odinger equation, we theoretically investigate the photoelectron spectrum of hydrogen atoms ionized by a pair of ultrashort, intense, and orthogonally pola...Based on numerical solutions of the time-dependent Schr ¨odinger equation, we theoretically investigate the photoelectron spectrum of hydrogen atoms ionized by a pair of ultrashort, intense, and orthogonally polarized laser pulses with a relative time delay in a pump–probe configuration. The pump pulse resonantly excites electrons from the 1s and 2p levels,inducing Rabi oscillations. The resulting dynamically enhanced Autler–Townes(AT) splitting is observed in the photoelectron energy spectrum upon interaction with the second probe pulse. In contrast to the previous parallel-polarization scheme, the proposed orthogonal-polarization configuration enables the resolution of dynamically enhanced AT splitting over a considerably wider range of probe photon energies.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
This paper reports how pyrite films were prepared by thermal sulfurization of magnetron sputtered iron films and characterized by X-ray absorption near edge structure spectra and X-ray photoelectron spectroscopy on a ...This paper reports how pyrite films were prepared by thermal sulfurization of magnetron sputtered iron films and characterized by X-ray absorption near edge structure spectra and X-ray photoelectron spectroscopy on a 4B9B beam line at the Beijing Synchrotron Radiation Facility. The band gap of the pyrite agrees well with the optical band gap obtained by a spectrophotometer. The octahedral symmetry of pyrite leads to the splitting of the d orbit into t2g and eg levels. The high spin and low spin states were analysed through the difference of electron exchange interaction and the orbital crystal field. Only when the crystal field splitting is higher than 1.5 eV, the two weak peaks above the white lines can appear, and this was approved by experiments in the present work.展开更多
Eu Mossbauer spectra of BaFBr:Eu phosphor are reported for the first time.The results show that f(Eu(2+) )<f(Eu(3+)) or <x2>Eu(2+)><x2>Eu(3+),which indicates that the attraction between phonons and E...Eu Mossbauer spectra of BaFBr:Eu phosphor are reported for the first time.The results show that f(Eu(2+) )<f(Eu(3+)) or <x2>Eu(2+)><x2>Eu(3+),which indicates that the attraction between phonons and Eu(2+) is stronger than that between phonons and Eu(3+),this may cause a faster increase of f(Eu=(2+)vs f(Eu(3+)) when temperature decreases as observed in the experiments.It is also found from Mossbauer investigation that when temperature decreases,the relative content of Eu(2+) decreases, while that of Eu(3+) increases.The temperature dependent Mossbauer spectra provide evidence for electron exchange or hopping between Eu(2+) or Eu(3+) sites in BaFBr lattice. The Mossbauer results are discussed and compared with the results of XPS and Photoluminescence studies.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.91021009 and 10874102)the Research Fund for the Doctoral Program of Higher Education,China (Grant No.200804220004)
文摘We investigate Autler-Townes splitting in the photoelectron spectra of K2 molecule driven by pump-probe pulses via employing the time-dependent wave packet approach. It is found that the magnitude of Aulter-Townes splitting varies with the wavelength of the intense laser pulse. In particular, the phenomenon of Aulter-Townes splitting vanishes for the far-off resonance of the pump pulse. Also, the split peaks of Autler Townes in the case of resonant pump pulse give us an approach to directly obtaining the transition dipole moment of a molecule.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60977063 and 10574039)the Foundation for Key Program of Ministry of Education China (Grant No. 206084)+1 种基金the Innovation Scientists and Technicians Troop Construction Projects of Henan Province,China (Grant No. 084100510011)the Innovation Talents of Institution of Higher Education of Henan Province,China (Grant No. 2006KYCX002)
文摘Wave packet dynamics of the Li2 molecule are investigated by using the time-dependent quantum wave packet method, and the time-resolved photoelectron spectra of the Li2 molecule are calculated. The time-resolved wave packet theory is used to reasonably interpret the phenomena of the photoelectron spectra for different parameters. Our calculation shows that the loss of the wave packets in the shelf state area of E1∑g＋ plays a prominent role in the process of photoionization with the increase of the delay time. Moreover, the oscillation of the wave packet on the E1∑g＋ curve symbolizes a decreasing process of energy.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61178028,11674243 and 11674242the National Basic Research Program of China under Grant No 2015CB755403
文摘We report our numerical simulation on the dynamic interference photoelectron spectra for a one-dimensional （1D） He model exposed to intense ultrashort extreme ultraviolet （XUV） laser pulses. The results demonstrate an unambiguous interference feature in the photoelectron spectra, and the interference is unveiled to originate from the dynamic Stark effect. The interference photoelectron spectra are prompted for intense sub-femtosecond XUV laser pulses in double ionization. The stationary phase picture is corroborated qualitatively in the two-electron system. The ability of probing the dynamic Stark effect by the photoelectron spectra in a pragmatic experiment of single-photon double ionization of He may shed light on further investigation on multi-electron atoms and molecules.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10974174 and 60676003)
文摘The energy band structure with type-I alignment at the PbTe/CdTe（111） heterojunction interface is determined by the ultraviolet photoelectron spectrum using synchrotron radiation. The valence band and conduction band offsets are obtained to be 0.09±0.12 and 1.19±0.12 eV, respectively. These results are in agreement with theoretically predicted ones. The accurate determination of the valence band and conduction band offsets is useful for the fundamental understanding of the mid-infrared light emission from the PbTe/CdTe heterostructures and its application in devices.
文摘The through--space and through--bond interactions in 1, 5 -- Cyclooctadiyne are studied. It is shown, with the assistance of improved MS--X_α method, that the through- space interactions decrease with the distance of the orbitals, and both through--space and through--bond interactions of 1, 5- Cyclooctadiyne are sizable but those two interactions oppose each other causing the net splitting to be small for π_z orbital. The calculated ionization potentials are in good agreement with the experiment of photoelectron spectra.
基金supported by the National Natural Science Foundation of China(Grant Nos.12074265,12234002,and 92250303)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2022A1515010329)。
文摘Based on numerical solutions of the time-dependent Schr ¨odinger equation, we theoretically investigate the photoelectron spectrum of hydrogen atoms ionized by a pair of ultrashort, intense, and orthogonally polarized laser pulses with a relative time delay in a pump–probe configuration. The pump pulse resonantly excites electrons from the 1s and 2p levels,inducing Rabi oscillations. The resulting dynamically enhanced Autler–Townes(AT) splitting is observed in the photoelectron energy spectrum upon interaction with the second probe pulse. In contrast to the previous parallel-polarization scheme, the proposed orthogonal-polarization configuration enables the resolution of dynamically enhanced AT splitting over a considerably wider range of probe photon energies.
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Project supported by the National Natural Science Foundation of China (Grant No 102750770)
文摘This paper reports how pyrite films were prepared by thermal sulfurization of magnetron sputtered iron films and characterized by X-ray absorption near edge structure spectra and X-ray photoelectron spectroscopy on a 4B9B beam line at the Beijing Synchrotron Radiation Facility. The band gap of the pyrite agrees well with the optical band gap obtained by a spectrophotometer. The octahedral symmetry of pyrite leads to the splitting of the d orbit into t2g and eg levels. The high spin and low spin states were analysed through the difference of electron exchange interaction and the orbital crystal field. Only when the crystal field splitting is higher than 1.5 eV, the two weak peaks above the white lines can appear, and this was approved by experiments in the present work.
文摘Eu Mossbauer spectra of BaFBr:Eu phosphor are reported for the first time.The results show that f(Eu(2+) )<f(Eu(3+)) or <x2>Eu(2+)><x2>Eu(3+),which indicates that the attraction between phonons and Eu(2+) is stronger than that between phonons and Eu(3+),this may cause a faster increase of f(Eu=(2+)vs f(Eu(3+)) when temperature decreases as observed in the experiments.It is also found from Mossbauer investigation that when temperature decreases,the relative content of Eu(2+) decreases, while that of Eu(3+) increases.The temperature dependent Mossbauer spectra provide evidence for electron exchange or hopping between Eu(2+) or Eu(3+) sites in BaFBr lattice. The Mossbauer results are discussed and compared with the results of XPS and Photoluminescence studies.
