Acta Phys. -Chim. Sin. ›› 2007, Vol. 23 ›› Issue (05): 746-750.doi: 10.3866/PKU.WHXB20070524

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Molecular Structure and Electronic Spectrumfor Methyl Vinyl Siloxane under the External Electric Field

XU Guo-Liang; XIAO Xiao-Hong; LIU Yu-Fang; SUN Jin-Feng; ZHU Zheng-He   

  1. College of Physics and Information Engineering, Henan Normal University, Xinxiang 453007, Henan Province, P. R. China; Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, P. R. China
  • Received:2006-09-28 Revised:2006-12-25 Published:2007-04-28
  • Contact: XU Guo-Liang E-mail:xugliang@hotmail.com

Abstract: The ground states of methyl vinyl siloxane under different intense electric fields ranging from0 to 0.04 a.u. were optimized using density functional theory DFT/B3P86 at 6-311++G(d,p) level. The excitation energies and oscillator strengths under the same intense applied electric fields were calculated employing the revised hybrid CIS-DFT method. The result showed that the electronic state, molecular geometry, total energy, dipole moment, and excitation energy were strongly dependent on the applied electric field. As the electric field changed from 0 to 0.03 a. u., the bond length of Si-O decreased because of the charge transfer induced by the applied electric field. Further increase of the electric field resulted in an increase of the bond length. The dipole moment of the ground state increased sharply with the applied field strength. As the electric field increased to 0.02 a.u., the total energy of the molecule reached the maximum -483.5393952 a.u.. Further increase of the electric field strengths resulted in a decrease of the total energy. The excitation energies of the first five excited states of methyl vinyl siloxane decreased as the increase of the applied electric field, indicating that the molecule was easy to be excited under electric field and hence could be easily dissociated.

Key words: Methyl vinyl siloxane, Electric field, Excited state, Hybrid CIS-DFT

MSC2000: 

  • O641