The growing radiation from those first stars ionized hydrogen atoms, split them back into protons and electrons.
随着初代恒星发出的辐射越来越大，电离的氢原子再次被分解为质子和电子。
Ionized hydrogen
原声例句
假如有如果
TED演讲（视频版） 2017年4月合集
And when the very first stars and galaxies switched on, they ionized that hydrogen.
当最早的恒星和星系启动时，它们将氢电离。
英语百科
Hydrogen ion
Hydrogen ion is recommended by IUPAC as a general term for all ions of hydrogen and its isotopes. Depending on the charge of the ion, two different classes can be distinguished: positively charged ions and negatively charged ions.