2013 Fiscal Year Final Research Report

Highly selective cryogenic reactions in solid hydrogen on pseudo cosmic dust surface

Research Project

Project/Area Number	23600005
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Quantum beam science
Research Institution	Nagoya University
Principal Investigator	KUMAGAI Jun 名古屋大学, エコトピア科学研究所, 准教授 (20303662)
Project Period (FY)	2011 – 2013
Keywords	solid parahydrogen / radical-radical reaction / cosmic dust / tunneling / distortion of lattice / ionizing radiation / electron spin resonance
Research Abstract	As a model of cosmic dust for bio-molecular growth in dark nebula at cryogenic temperature, a mixture of silica gel with solid parahydrogen was used for deterring the reactions of H atoms and other radicals at 4.2 K. We found that H atoms and methyl radicals never react in solid parahydrogen even though H atoms were diffused in solid parahydrogen. H atoms also did not react with TEMPO radicals adsorbed on the silica gels. H atoms can diffuse in solid parahydrogen only by tunneling reaction of H abstraction reaction. Solute molecules as methyl radicals or silica gels may distort the lattice structure of solid parahydrogen, to make difficult for diffusion of H atoms by the tunneling. This can be the main reason why such radical-radical reactions could not take place at 4.2 K.