中国物理B ›› 2013, Vol. 22 ›› Issue (7): 73301-073301.doi: 10.1088/1674-1056/22/7/073301

• ATOMIC AND MOLECULAR PHYSICS • 上一篇    下一篇

TDDFT study of excitation of water molecules with short laser pulses

王志萍, 吴亚敏, 张秀梅, 鲁超   

  1. School of Science, Jiangnan University, Wuxi 214122, China
  • 收稿日期:2012-10-30 修回日期:2012-11-22 出版日期:2013-06-01 发布日期:2013-06-01
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 61178032), the Fundamental Research Funds for the Central Universities of China (Grant No. 11A21), and the "Eleven Five" Planning Issues for Higher Education of Jiangsu Province, China (Grant No. JS053).

TDDFT study of excitation of water molecules with short laser pulses

Wang Zhi-Ping (王志萍), Wu Ya-Min (吴亚敏), Zhang Xiu-Mei (张秀梅), Lu Chao (鲁超)   

  1. School of Science, Jiangnan University, Wuxi 214122, China
  • Received:2012-10-30 Revised:2012-11-22 Online:2013-06-01 Published:2013-06-01
  • Contact: Wang Zhi-Ping E-mail:zpwang03247@163.com
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 61178032), the Fundamental Research Funds for the Central Universities of China (Grant No. 11A21), and the "Eleven Five" Planning Issues for Higher Education of Jiangsu Province, China (Grant No. JS053).

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摘要： We explore the excitation of water molecules subject to short and intense laser pulses in the frame of time-dependent density function theory (TDDFT) at the level of the time-dependent local-density approximation (TDLDA), applied to valence electrons, coupled non-adiabatically to molecular dynamics (MD) of ions. We first study the optical absorption spectra of the water molecule as an observable in the “linear” domain and results are in good agreement with experiments. We then explore the influence of the laser frequency on the excitation. It is found that when the laser frequency is off-resonant or highly above the resonant region, the excitations are weak whereas for the resonant frequency case, the ionization is enhanced and and bond lengths are enlarged. Furthermore, a direct coupling of ions with the laser pulse with the off-resonant frequency is found when investigating the OH bond lengths. We finally study the effect of laser intensity on the excitation of H2O and it is found that ionization increases when the laser intensity varies from low to high and we observe stable vibrations to Coulomb fragmentation when the ionization is up to typically two more charge unit.

关键词: time-dependent local-density approximation, ionization, optical absorption spectra

Abstract: We explore the excitation of water molecules subject to short and intense laser pulses in the frame of time-dependent density function theory (TDDFT) at the level of the time-dependent local-density approximation (TDLDA), applied to valence electrons, coupled non-adiabatically to molecular dynamics (MD) of ions. We first study the optical absorption spectra of the water molecule as an observable in the “linear” domain and results are in good agreement with experiments. We then explore the influence of the laser frequency on the excitation. It is found that when the laser frequency is off-resonant or highly above the resonant region, the excitations are weak whereas for the resonant frequency case, the ionization is enhanced and and bond lengths are enlarged. Furthermore, a direct coupling of ions with the laser pulse with the off-resonant frequency is found when investigating the OH bond lengths. We finally study the effect of laser intensity on the excitation of H2O and it is found that ionization increases when the laser intensity varies from low to high and we observe stable vibrations to Coulomb fragmentation when the ionization is up to typically two more charge unit.

Key words: time-dependent local-density approximation, ionization, optical absorption spectra

中图分类号:  (Molecular spectra)

  • 33.20.-t
34.50.Gb (Electronic excitation and ionization of molecules) 36.40.Vz (Optical properties of clusters)