• Spectroscopy and Spectral Analysis
  • Vol. 36, Issue 5, 1317 (2016)
Abai Alghazi1、2、*, LIU Jing1, DAI Kang1, and SHEN Yi-fan1
Author Affiliations
  • 1[in Chinese]
  • 2[in Chinese]
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    DOI: 10.3964/j.issn.1000-0593(2016)05-1317-06 Cite this Article
    Abai Alghazi, LIU Jing, DAI Kang, SHEN Yi-fan. Quantum State-Resolved Energy Redistribution of CO2 from Collisions with Highly Vibrationally Excited NaH[J]. Spectroscopy and Spectral Analysis, 2016, 36(5): 1317 Copy Citation Text show less

    Abstract

    Degenerate stimulated hyper-Raman pumping is used to excite high vibrational states of NaH. The full state-resolved distribution of scattered CO2(0000, J) molecules from collisions with excited NaH(ν″=14, J=21) was reported. The nascent number densities of NaH were determined from absorption measurements at times t=1 μs as the laser to prepare NaH(ν″, J″). Absorption signals were converted to NaH(ν″, J″) population using absorption coefficients and the transient Doppler-broadened linewidths. The nascent CO2(0000, J) population were obtained from transient overtone laser induced fluorescence line intensity measured at short times relative to the time between collisions. The scattered CO2(0000, J=2~80) molecules had a biexponential rotational distribution. Fitting the data with a two-component exponential model yielded CO2 product distributions with Trot=(650±80) and (1 531±150) K. The cooler distribution accounted for 79% of the scattered population and resulted from elastic or weakly inelastic collisions that induced very little rotational excitation in CO2. The hotter distribution involved large changes in CO2 rotational energy and accounted for 21% of collision. Nascent translational energy profiles for scattered CO2(0000, J=60~80) were measured using high resolution transient overtone fluorescence. The relative translational energy of the scattered molecules increased as a function of final CO2 rotational state with 〈ΔErel〉=582 cm-1 for J=60, and 2 973 cm-1 for J=80. Energy transfer rates were determined for the full J-state distribution by monitoring the change of the nascent population. The total rate constant for appearance of scattered CO2(0000) was kapp=(7.2±1.8)×10-10 cm3·mol-1·s-1. The depletion for the low-J CO2 states was involved in the collisional energy transfer of the initial distribution. For J=2~38, the average rate constant for depletion of scattered CO2(0000) is 〈kdep〉=(6.9±1.7)×10-10 cm3·mol-1·s-1.
    Abai Alghazi, LIU Jing, DAI Kang, SHEN Yi-fan. Quantum State-Resolved Energy Redistribution of CO2 from Collisions with Highly Vibrationally Excited NaH[J]. Spectroscopy and Spectral Analysis, 2016, 36(5): 1317
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