free-ion model

例句：

1. 1. The free-ion model is a popular approach in quantum chemistry to describe the behavior of atoms and molecules in an electric field.
   自由离子模型是量子化学中描述原子和分子在电场中行为的一种流行方法。
2. 2. In this model, electrons are considered as being free from any external forces except gravity.
   在这个模型中，电子被认为是不受任何外部力量
3. 3. The free-ion model has been widely used in the development of new materials and devices.
   自由离子模型在新材料和设备的研发中被广泛使用。