State-Specific Collision Dynamics of Molecular Super Rotors with Oriented Angular Momentum

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• 作者：Matthew J. Murray ; Hannah M. Ogden ; Carlos Toro ; Qingnan Liu ; David A. Burns ; Millard H. Alexander ; Amy S. Mullin
• 刊名：Journal of Physical Chemistry A
• 出版年：2015
• 出版时间：December 17, 2015
• 年：2015
• 卷：119
• 期：50
• 页码：12471-12479
• 全文大小：638K
• ISSN：1520-5215

文摘

An optical centrifuge pulse drives carbon dioxide molecules into ultrahigh rotational states with rotational frequencies of 蠅 鈮?32 THz based on the centrifuge frequency at the full width at half-maximum of the spectral chirp. High-resolution transient IR absorption spectroscopy is used to measure the time-evolution of translational and rotational energy for a number of states in the range of J = 0鈥?00 at a sample pressure of 5鈥?0 Torr. Transient Doppler profiles show that the products of super rotor collisions contain substantial amounts of translational energy, with J-dependent energies correlating to a range of 螖J propensities. The transient population in J = 100 is short-lived, indicating rapid relaxation of high J states; populations in J = 36, 54, and 76 increase overall as the super rotor energy is redistributed. Transient line profiles for J = 0 and 36 are consistently narrower than the initial ambient sample temperature, showing that collision cross sections for super rotors increase with decreasing collision energy. Quantum scattering calculations on Ar鈥揅O₂(j) collisions are used to interpret the qualitative features of the experimental results. The results of this study provide the groundwork for developing a more complete understanding of super rotor dynamics.