spontaneous ionization

例句：

1. 1.The spontaneous ionization of the gas led to a sudden increase in the electrical resistance.
   气体的自发电离导致电阻突然增加。
2. 2.In this experiment, we observed spontaneous ionization of water molecules at room temperature.
   在这个实验中，我们观察到水分子在室温下自发电离。
3. 3.The spontaneous ionization of the gas is a crucial step in the process of chemical reactions.
   气体的自发电离是化学反应过程中的关键步骤。