Vibrational transition spectra of H2＋ in an ultra-strong magnetic field are determined. The validity of Born- Oppenheimer approximation is analyzed based on one-center method and B-spline basis sets. It is shown that...Vibrational transition spectra of H2＋ in an ultra-strong magnetic field are determined. The validity of Born- Oppenheimer approximation is analyzed based on one-center method and B-spline basis sets. It is shown that Born- Oppenheimer approximation is reliable for the investigation on the ground state and low excited states of H2＋ subjected to the strong magnetic field. Furthermore, it is found that the vibrational transition spectra from lσg, lπu, and 1δg states lie in infrared, visible, and ultraviolet ranges with increasing magnetic field strength.展开更多
High-order harmonic generation （HHG） of a helium model atom in an intense laser field has been numerically investigated. The influence of electron correlation on HHG is analysed by changing the strength between the ...High-order harmonic generation （HHG） of a helium model atom in an intense laser field has been numerically investigated. The influence of electron correlation on HHG is analysed by changing the strength between the electrons. The numerical results show that as the electron interaction strength becomes small, the first ionization energy increases rapidly, which results in the decrease in ionization. So the conversion efficiency of the high harmonic lying in the plateau decreases greatly, while the cutoff harmonic order in the harmonic spectrum increases.展开更多
The important features of the rescattering trajectories in strong field ionization process such as the cutoff of the return energy at 3.17Up and that of the final energy at 10Up are obtained, based on the adiabatic ap...The important features of the rescattering trajectories in strong field ionization process such as the cutoff of the return energy at 3.17Up and that of the final energy at 10Up are obtained, based on the adiabatic approximation in which the initial momentum of the electron is assumed to be zero. We theoretically study the nonadiabatic effect by assuming a nonzero initial momentum on the rescattering trajectories based on the semiclassical simpleman model. We show that the nonzero initial momentum will modify both the maximal return energy at collision and the final energy after backward scattering, but in different ways for odd and even number of return trajectories. The energies are increased for even number of returns but are decreased for odd number of returns when the nonzero （positive or negative） initial momentum is applied.展开更多
We perform a theoretical investigation on the control over the atomic excitation of Rydberg states with shaped intense ultrashort laser pulses. By numerically solving the time-dependent Schr?dinger equation（TDSE）, w...We perform a theoretical investigation on the control over the atomic excitation of Rydberg states with shaped intense ultrashort laser pulses. By numerically solving the time-dependent Schr?dinger equation（TDSE）, we systematically study the dependence of the population of the Rydberg states on the π phase step position in the frequency spectra of the laser pulse for different intensities, central wavelengths and pulse durations. Our results show that the Rydberg excitation process can be effectively modulated using shaped intense laser pulses with the laser intensity as high as 1 × 1014 W/cm2. Our work also have benefit to the future investigation to find out the dominant mechanism behind the excitation of Rydberg states in strong laser fields.展开更多
We perform Hartree–Fock calculations to obtain occupied orbitals for triatomic molecule CO_(2),based on one-center method and B-splines to deal with cusps and speed up convergence.Both the orbital energies and charge...We perform Hartree–Fock calculations to obtain occupied orbitals for triatomic molecule CO_(2),based on one-center method and B-splines to deal with cusps and speed up convergence.Both the orbital energies and charge distribution are in good accordance with the reference data.The valence orbital is propagated with single-active-electron approximation,and the alignment-dependent ionization yield peaks about 40°.However,there are discrepancies between our results and the experimental data,and many-electron effects may need to be exploited further to describe them.展开更多
The three-dimensional electron-electron correlation in an elliptically polarized laser field is investigated based on a semiclassical model. Asymmetry parameter α of the correlated electron momentum distribution is u...The three-dimensional electron-electron correlation in an elliptically polarized laser field is investigated based on a semiclassical model. Asymmetry parameter α of the correlated electron momentum distribution is used to quantitatively describe the electron-electron correlation. The dependence of α on elliptieity e is totally different in three directions. For the z direction （maJor polarization direction）, α first increases and reaches a maximum at ε = 0.275, then it decreases quickly. For the y direction in which the laser field is always absent, the ellipticity has a minor effect, and the asymmetry parameter fluctuates around α = -0.15. However, for the x direction （minor polarization direction）, α increases monotonously with ellipticity though starts from the same value as in the y direction when ε = 0. The behavior of α in the x direction actually indicates a transformation from the Coulomb interaction dominated correlation to the laser field dominated correlation. Therefore, our work provides an efficient way to control the three-dimensional electron electron correlation via an elliptically polarized intense laser field.展开更多
We calculate the time-energy distribution(TED)and ionization time distribution(ITD)of photoelectrons emitted by a doubleextreme-ultraviolet(XUV)pulse and a two-color XUV-IR pulse using the Wigner distribution-like fun...We calculate the time-energy distribution(TED)and ionization time distribution(ITD)of photoelectrons emitted by a doubleextreme-ultraviolet(XUV)pulse and a two-color XUV-IR pulse using the Wigner distribution-like function based on the strong field approximation.For a double-XUV pulse,besides two identical broad distributions generated by two XUV pulses,many interference fringes resulting from the interference between electrons generated,respectively,by two pulses appear in the TED.After adding an IR field,the TED intuitively exhibits the effect of the IR field on the electron dynamics.The ITDs during two XUV pulses are no longer the same and show the different changes for the different two-color fields,the origin of which is attributed to the change of the electric field induced by the IR field.Our analysis shows that the emission time of electrons ionized during two XUV pulses mainly depends on the electric field of the combined XUV pulse and IR pulse.展开更多
基金Supported by the National Basic Research Program of China (Grant No. 2010CB832803)
文摘Vibrational transition spectra of H2＋ in an ultra-strong magnetic field are determined. The validity of Born- Oppenheimer approximation is analyzed based on one-center method and B-spline basis sets. It is shown that Born- Oppenheimer approximation is reliable for the investigation on the ground state and low excited states of H2＋ subjected to the strong magnetic field. Furthermore, it is found that the vibrational transition spectra from lσg, lπu, and 1δg states lie in infrared, visible, and ultraviolet ranges with increasing magnetic field strength.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10974224)the National Basic Research Program of China (Grant No. 2010CB832803)
文摘High-order harmonic generation （HHG） of a helium model atom in an intense laser field has been numerically investigated. The influence of electron correlation on HHG is analysed by changing the strength between the electrons. The numerical results show that as the electron interaction strength becomes small, the first ionization energy increases rapidly, which results in the decrease in ionization. So the conversion efficiency of the high harmonic lying in the plateau decreases greatly, while the cutoff harmonic order in the harmonic spectrum increases.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11425414 and 11504215the Scientific Research Training Program of Shanxi University
文摘The important features of the rescattering trajectories in strong field ionization process such as the cutoff of the return energy at 3.17Up and that of the final energy at 10Up are obtained, based on the adiabatic approximation in which the initial momentum of the electron is assumed to be zero. We theoretically study the nonadiabatic effect by assuming a nonzero initial momentum on the rescattering trajectories based on the semiclassical simpleman model. We show that the nonzero initial momentum will modify both the maximal return energy at collision and the final energy after backward scattering, but in different ways for odd and even number of return trajectories. The energies are increased for even number of returns but are decreased for odd number of returns when the nonzero （positive or negative） initial momentum is applied.
基金Project supported by the National Natural Science Foundation of China(Grant No.11874246)
文摘We perform a theoretical investigation on the control over the atomic excitation of Rydberg states with shaped intense ultrashort laser pulses. By numerically solving the time-dependent Schr?dinger equation（TDSE）, we systematically study the dependence of the population of the Rydberg states on the π phase step position in the frequency spectra of the laser pulse for different intensities, central wavelengths and pulse durations. Our results show that the Rydberg excitation process can be effectively modulated using shaped intense laser pulses with the laser intensity as high as 1 × 1014 W/cm2. Our work also have benefit to the future investigation to find out the dominant mechanism behind the excitation of Rydberg states in strong laser fields.
基金Supported by the National Natural Science Foundation of China under Grant No 11274348the National Basic Research Program of China under Grant Nos 2010CB832803 and 2013CB922203the Major Research Plan of the National Natural Science Foundation of China under Grant No 91121017.
文摘We perform Hartree–Fock calculations to obtain occupied orbitals for triatomic molecule CO_(2),based on one-center method and B-splines to deal with cusps and speed up convergence.Both the orbital energies and charge distribution are in good accordance with the reference data.The valence orbital is propagated with single-active-electron approximation,and the alignment-dependent ionization yield peaks about 40°.However,there are discrepancies between our results and the experimental data,and many-electron effects may need to be exploited further to describe them.
基金Supported by the National Key Program for S&T Research and Development under Grant No 2016YFA0401100the National Basic Research Program of China under Grant No 2013CB922201the National Natural Science Foundation of China under Grant Nos 11504215,11374197,11334009 and 11425414
文摘The three-dimensional electron-electron correlation in an elliptically polarized laser field is investigated based on a semiclassical model. Asymmetry parameter α of the correlated electron momentum distribution is used to quantitatively describe the electron-electron correlation. The dependence of α on elliptieity e is totally different in three directions. For the z direction （maJor polarization direction）, α first increases and reaches a maximum at ε = 0.275, then it decreases quickly. For the y direction in which the laser field is always absent, the ellipticity has a minor effect, and the asymmetry parameter fluctuates around α = -0.15. However, for the x direction （minor polarization direction）, α increases monotonously with ellipticity though starts from the same value as in the y direction when ε = 0. The behavior of α in the x direction actually indicates a transformation from the Coulomb interaction dominated correlation to the laser field dominated correlation. Therefore, our work provides an efficient way to control the three-dimensional electron electron correlation via an elliptically polarized intense laser field.
基金partially supported by the National Key Research and Development Program of China(Nos.2019YFA0307700and 2016YFA0401100)the National Natural Science Foundation of China(NSFC)(Nos.11774361,11775286,11804405,and 12047576)。
文摘We calculate the time-energy distribution(TED)and ionization time distribution(ITD)of photoelectrons emitted by a doubleextreme-ultraviolet(XUV)pulse and a two-color XUV-IR pulse using the Wigner distribution-like function based on the strong field approximation.For a double-XUV pulse,besides two identical broad distributions generated by two XUV pulses,many interference fringes resulting from the interference between electrons generated,respectively,by two pulses appear in the TED.After adding an IR field,the TED intuitively exhibits the effect of the IR field on the electron dynamics.The ITDs during two XUV pulses are no longer the same and show the different changes for the different two-color fields,the origin of which is attributed to the change of the electric field induced by the IR field.Our analysis shows that the emission time of electrons ionized during two XUV pulses mainly depends on the electric field of the combined XUV pulse and IR pulse.
