Nonequilibrium Vibrational Excitation of OH Radicals Generated During Multibubble Cavitation in Water

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• 作者：Abdoul Aziz Ndiaye ; Rachel Pflieger ; Bertrand Siboulet ; John Molina ; Jean-Fran莽ois Dufr锚che ; Sergey I. Nikitenko
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：May 24, 2012
• 年：2012
• 卷：116
• 期：20
• 页码：4860-4867
• 全文大小：461K
• 年卷期：v.116,no.20(May 24, 2012)
• ISSN：1520-5215

文摘

The sonoluminescence (SL) spectra of OH(A²危⁺) excited state produced during the sonolysis of water sparged with argon were measured and analyzed at various ultrasonic frequencies (20, 204, 362, 609, and 1057 kHz) in order to determine the intrabubble conditions created by multibubble cavitation. The relative populations of the OH(A²危⁺) v鈥?/i> = 1鈥? vibrational states as well as the vibronic temperatures (T_v, T_e) have been calculated after deconvolution of the SL spectra. The results of this study provide evidence for nonequilibrium plasma formation during sonolysis of water in the presence of argon. At low ultrasonic frequency (20 kHz), a weakly excited plasma with Brau vibrational distribution is formed (T_e 0.7 eV and T_v 5000 K). By contrast, at high-frequency ultrasound, the plasma inside the collapsing bubbles exhibits Treanor behavior typical for strong vibrational excitation. The T_e and T_v values increase with ultrasonic frequency, reaching T_e 1 eV and T_v 9800 K at 1057 kHz.