Abstract : Sonoluminescence (SL) spectra of a very dry [BEPip][NTf 2 ] ionic liquid were measured in the first minutes of sonication under Ar. The intense sonoluminescence allowed us to monitor the time-evolution of the SL spectra. Several molecular emissions were observed. Rovibronic temperatures of C 2 and CN were determined giving vibrational temperatures of 5800 AE 500 K and 6000 AE 500 K and rotational temperatures (i.e. translational or gas temperatures) of 4000 AE 500 K. These temperatures stay remarkably constant during the sonolysis, while SL spectra undergo strong changes that illustrate the very fast evolution of the plasma during the first minutes of sonication. The expected strong decrease in the plasma electron energy also reflects in the evolution of the populations of CH electronically excited states. The physical meaning of temperatures derived from molecular emissions in SL spectra is discussed.
https://hal.univ-lorraine.fr/hal-02105350
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Submitted on : Saturday, November 21, 2020 - 11:45:53 AM Last modification on : Friday, March 19, 2021 - 9:14:02 AM
Rachel Pflieger, Manuel Lejeune, Cédric Noel, Thierry Belmonte, Sergey I. Nikitenko, et al.. Diagnosing the plasma formed during acoustic cavitation in [BEPip][NTf2] ionic liquid. Physical Chemistry Chemical Physics, Royal Society of Chemistry, 2019, 21 (3), pp.1183-1189. ⟨10.1039/c8cp06967k⟩. ⟨hal-02105350⟩