Optical-optical double resonance spectroscopy is used to obtain total rate constants, electronic branching ratios, and vibrational product state distributions for non-adiabatic transitions among the first-tier ion-pair states of the I2 molecule excited to the E 0g+, vE = 8, 13, 19; JE ≈ 55 rovibronic levels in collisions with M = I2, N2 and CO2. It is shown that I2 (E over(→, M) D) near-resonant transitions are caused by the interaction between the transition dipole moment of I2(E-D) and the electric quadrupole moment of M. Besides, there are transitions induced by polarization interactions of the collision partners. Wide non-resonant vibrational distributions at the final states correspond to them. The I2(D and β) state vibrational levels populated in the transitions accompanied by excitation of IR active vibrational mode, CO2(0110 ← 000) ν2e1u(667 cm-1), are observed. It is shown that rotational excitation of the collision partners can compensate energy mismatch between initial and final rovibrational levels.

Original languageEnglish
Pages (from-to)173-183
Number of pages11
JournalChemical Physics
Volume342
Issue number1-3
DOIs
StatePublished - 6 Dec 2007

    Research areas

  • Collisions, Iodine ion-pair states, Non-adiabatic transitions, Optical-optical double resonance

    Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

ID: 87819812