Research reveals the "geometric phase" effect in chemical reactions

Wang Xing’an, a professor at the University of Science and Technology of China, and Sun Zhigang, Zhang Donghui, Yang Xueming, and other researchers at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, use the independently developed cross-molecule ion imaging device with the highest resolution in the world, combined with high-precision theoretical analysis of quantum molecular reaction kinetics.In-depth study of the “geometric phase” effect in the H+HD reaction and a major breakthrough. Related results were published online in the journal Science on December 14.

Research reveals the "geometric phase" effect in chemical reactions

Wang Xing’an and Yang Xueming independently developed a unique cross-molecular beam reaction kinetics research device combining threshold laser ionization technology and ion velocity imaging technology, so that the scattering angle resolution of the experimentally obtained hydrogen atom product reaches the same kind of instrument. The highest level.

  Using this device, the research team successfully measured the full quantum state resolved product velocity image of the H+HD→H2+D reaction, and experimentally observed the rapidly oscillating structure of the forward-distributed angular distribution of the H2 product. In theoretical calculations, Sun Zhigang et al. developed a unique dynamic theory describing the geometric effects in chemical reactions. Based on the high-precision potential energy surface developed by Zhang Donghui et al., it was found by accurate quantum dynamic analysis that only the “geometric phase” effect was introduced. The theoretical calculations can correctly describe the experimentally observed forward scattering oscillation structure.

  More than half a century ago, scientists discovered that under the Bonn-Oppenheimer approximation or adiabatic approximation, “geometric phase” must be introduced to accurately describe the quantum dynamic behavior of these systems. The introduction of “geometric phase” changes the dynamical interference behavior of quantum systems, which is known as the “geometric phase” effect.

  The researchers revealed the unique role of “geometric phase” in chemical reactions and the physical nature of the “geometric phase” effect, which is of great significance for the study of quantum systems with widely conical intersections. At the same time, they also experimentally found and confirmed a new reaction mechanism of this important reaction system in high-energy reaction, which is of great significance for fundamentally understanding the high-energy reaction kinetics of this important system.

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