水素分子の形成とオルトーパラ転換 ― 宇宙科学との関係を考える
Molecular-hydrogen generation and ortho-para conversion - Relation with astrophysics

福谷　克之（Katsuyuki FUKUTANI）
東京大学 生産技術研究所（Institute of Industrial Science, The University of Tokyo）

Hydrogen is the most abundant element in the universe and a main constituent of the interstellar media. Recombinative formation of molecular hydrogen from atomic hydrogen leads to molecular clouds, which is regarded as a precursor state of star formation. Molecular hydrogen exists in nuclear-spin isomers designated as ortho and para species according to the total nuclear spin of 1 and 0, respectively. Whereas the transition between the ortho and para species and molecular hydrogen formation are extremely slow in gas phase, both processes are promoted through interaction with solid surfaces. In recent years, the ortho-para ratio of molecular hydrogen in space and planetary environments has been experimentally observed by infrared satellite observatory, which often reveals deviation from the molecular-cloud temperature. This is expected to provide us with information on evolution of molecular clouds and star formation. In these regards, we experimentally investigate molecular-hydrogen formation and ortho-para conversion on solid surfaces in the laboratory, and discuss the physical mechanism.

Place: 2F Conf. room（1236） / 研究管理棟２階会議場（1236号室）