Reaction dynamics of antiprotonic hydrogen formation in collisions between antiprotons and molecules

反质子与分子碰撞中反质子氢形成的反应动力学

• 批准号: 15540385
• 负责人: SAKIMOTO Kazuhiro
• 金额: $ 1.73万
• 依托单位: Japan Aerospace Exploration Agency
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15540385/
• 关键词: antiproton; antiprotonic hydrogen; antiprotonic atom; exotic atom; atomic and molecular physics; chemical reaction; antiproton capture; 反陽子水素原子; 反陽子ヘリウム原子; 反陽子・陽子消滅; 反水素原子; ヘリウムイオン; 共鳴散乱; 電離; 水素分子イオン; ミューオン; プロトニウム; 原子分子衝突; 断熱ポテンシャル曲面

Low-energy antiproton collisions with atomic or molecular ions was investigated using a wave-packet-propagation full-quantum-mechanical method or a quantum-classical hybrid (i.e., semiclassical) approximation. It is found that the adiabatic picture (i.e., Born-Oppenheinmer separation) is appropriate in a large sense.In the case of atomic ion targets, the antiproton capture is a typical non-adiabatic process because the electron must be emitted in this process, and hence occurs less frequently. However, even at very low energies, the capture probability is in fact small but finite still for large angular momenta. Correspondingly, the cross section for the non-adiabatic process diverges in the zero energy limit. This happens due to the peculiarity that the Coulomb force range is longer than the centrifugal one. Importance of a Rydberg series of resonances in the capture process is also 0found.In the case of molecular ion targets, the adiabatic condition is satisfied much better because t … More he electron can escape from the antiproton by forming a neutral atom or molecule. At the same the, the formation of aniti porotonic atoms becomes possible even in the adiabatic approximation. For the molecular ion targets, the antiprotonic atom formation can be treated as the collisions on a single adiabatic (Born-Oppenheimer) potential energy surface (PES), in the same manner as chemical reaction problems. The PES was caclculated for teh antiproton and hydrogen molecular ion system. A classicla trajectory Monte Carlo method was applied to the collision calculation. It is found that the dissociative dynamics plays a critical role in antiptotonic hydrogen (protonium) formation, the consequently the molecular target is much more effective in antiproton capture than the atomic target.I carried out the calculation also for collisions of hydrogen molecular ions with negative muons and kaons, and investigated the mass effect on the reaction dynamis. It is found that the antiproton capture has a remarkable mass dependence. This is clearly in contrast to the negligible mass dependence. This is clearly in contrast to the negligiblemass dependence of the antiproton capture by atom in which the non-adiabatic coupling plays a dominant role. Less

使用波包传播全量子力学方法或量子经典混合（即半经典）近似研究了与原子或分子离子的低能反质子碰撞，发现绝热图（即玻恩-奥本海因默分离）在很大程度上是合适的。对于原子离子目标，反质子捕获是典型的非绝热过程，因为在这个过程中，电子必须被发射，因此发生的频率较低。然而，即使在非常低的能量下，捕获概率实际上也很小，但对于大角动量来说仍然是有限的，相应地，非绝热过程的横截面会发散。在零能量极限下，这种情况的发生是由于库仑力范围比离心力范围长的特殊性，在捕获过程中里德伯系列共振的重要性也是 0 发现的。离子目标，绝热条件得到更好的满足，因为电子可以通过形成中性原子或分子来逃离反质子，同时，即使在绝热近似下，反质子原子的形成也是可能的。分子离子目标，反质子原子的形成可以被视为单个绝热（玻恩-奥本海默）势能面（PES）上的碰撞，以相同的方式作为化学反应问题，对反质子和氢分子离子系统进行了计算，将经典的轨迹蒙特卡罗方法应用于碰撞计算，发现解离动力学在反质子氢（质子）的形成中起着关键作用。因此，分子靶在反质子捕获方面比原子靶更有效。我还对氢分子离子与负μ介子和Ka介子的碰撞进行了计算，并研究了质量效应发现反质子俘获具有显着的质量依赖性，这与非绝热耦合中原子的反质子俘获的可忽略的质量依赖性形成鲜明对比。较少发挥主导作用。

项目成果

K.Sakimoto: "Collinear study of protonium formation in collisions of antiprotons with hydrogen molecular ions"Nucl.Instr.and Meth.B. 214. 131-134 (2004)

K.Sakimoto：“反质子与氢分子离子碰撞中质子形成的共线研究”Nucl.Instr.and Meth.B。

Chemical reaction of negative particles pbar, kaon, and muon with molecular ions

负粒子pbar、kaon、μon与分子离子的化学反应

• 发表时间: 2004
• 期刊: Chem.Phys.Letters 393
• 作者: K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto
• 通讯作者: K.Sakimoto

K.Sakimoto: "Full quantum-mechanical study of protonium formation in slow collisions of antiprotons with hydrogen atoms"Physica Scripta. (印刷中). (2004)

K. Sakimoto：“反质子与氢原子缓慢碰撞中质子形成的完整量子力学研究”Physica Scripta（2004 年出版）。

Collinear study of protonium formation in collisions of antiprotons with hydrogen molecular ions

反质子与氢分子离子碰撞中质子形成的共线研究

• 发表时间: 2004
• 期刊: Nucl. Instr. and Meth. B 214
• 作者: K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto
• 通讯作者: K.Sakimoto

Chemical reaction of negative particles pbar, K-, and mu- with molecular ions

负粒子pbar、K-、mu-与分子离子的化学反应

• 发表时间: 2004
• 期刊: Chem.Phys.Letters 393
• 作者: K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto;K.Sakimoto
• 通讯作者: K.Sakimoto