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A04 Experimental study of gas-phase chemical reactions by advanced beam technologies

The ion-molecule reactions play a key role in the gas-phase chemistry of cold interstellar clouds. Chemical reaction network models have been successful in understanding the chemical abundance of the clouds assuming the rate constants of these reactions have more or less the same Arrhenius-like temperature dependence at cryogenic temperatures around 10 K. However, recent studies have shown that some of the ion-molecule reactions exhibit a characteristic temperature at intermediate temperatures around 10-300 K. At these temperatures, the shape of reaction barriers has a significant effect on the reaction probability and branching ratio between reaction paths. Therefore, to understand the complex gas-phase chemistry of the warm clouds in the planet-forming regions, we are keen to develop a new chemical model beyond the conventional methods limited to the cryogenic environments. The gas-phase experiment group (A04) will experimentally investigate the rate constants and their temperature dependence of important ion-neutral reactions at intermediate temperatures around 10-300 K. Taking advantage of the state-of-the-art particle beam technologies, we will develop novel experimental studies in three subgroups, the merged-beam, the ion trap, and the drift tube experiments. We will put focus on the critical subjects; (1) reaction rates of chemically active species (neutral atoms and polar molecules) and their temperature dependence, (2) the reaction branching ratios involving structural isomers, and (3) the isotope effects in the above reactions. By understanding the elementary processes of the gas-phase atomic and molecular reactions, we will explore the chemistry of the planet-forming region in collaboration with the theoretical and observational groups.


A04 Project Group Leader:

Yuji Nakano

Associate Professor,

Department of Physics,

College of Science,

Rikkyo University

中野 祐司
Yuji Nakano

Rikkyo University

Group Leader, Merged-beam experiments on ion-neutral reactions

椎名 陽子
Yoko Shiina

Rikkyo University

Development of neutral atomic beam

飯田 進平
Shimpei Iida

Tokyo Metropolitan University

Isomer-selected ion-molecule reactions

田沼 肇
Hajime Tanuma

Tokyo Metropolitan University

Variable-temperature ion-molecule reactions

岡田 邦宏
Kunihiro Okada

Sophia University

Ion trap experiments on the polar molecules

木村 直樹
Naoki Kimura


Developments of a cold molecular ion source

大下 慶次郎
Keijiro Ohshimo

Tohoku University

[The 1st Public Research Leader]
"Quantitative Observation of Temperature Dependence of Rate Constants in Carbon Chain Growth Reactions of Molecules and Clustered Negative Ions"

井口 佳哉
Yoshiya Inokuchi

Hiroshima University

[The 1st Public Research Leader]
"Understanding the Gas-phase spectroscopy of ionic complexes containing aromatic molecules at extremely low temperatures and their photochemical reaction process"

高口 博志
Hiroshi Kohguchi

Hiroshima University

[The 1st Public Research Leader]
"Development of Simultaneous Control of Quantum States and Reaction Temperatures for Pioneering Research in Quasi-Low Temperature Chemistry"

水瀬 賢太
Kenta Mizuse

Kitasato University

[The 1st Public Research Leader]
"Realization of broadband and high-resolution molecular spectroscopy for ionic species and its application to interstellar ion chemistry research"

中井 陽一
Yoichi Nakai


[The 1st Public Research Leader]
"Cooperative Reactions between Gas-phase Ions and Interstellar Dust Surfaces: Search for New Reaction Processes in the Formation of Complex Organic Molecules"

奥村 拓馬
Takuma Okumura


[The 1st Public Research Leader]
"Development of Next-Generation Neutral Molecule Detection System to Elucidate the Whole Picture of Interstellar Chemical Reactions"

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