低能质子对乙炔分子电子激发效应的研究

探索低能离子特别是质子碰撞对有机分子的电子激发效应对理解低能离子对生物有机体的辐照损伤效应是非常重要的.本文采用第一性原理分子动力学方法模拟低能质子与乙炔分子之间碰撞的动力学过程,研究由于低能质子碰撞导致的乙炔分子的电子激发效应,碰撞过程中质子的能量损失以及靶分子价带上的激发电子的数目,揭示了电子激发效应是电子能量损失的主要机制,证明了关于电子阻止本领的传统线性理论模型不能很好地描述低能离子穿透分子靶时的电子能损,并且阐明了其中的原因.

Study of the Electronic Excitation Effects of AcetyleneInduced by Low-energy Protons

In order to understand the irradiation damage effects of low-energy ions on the biological organisms,it is very important to study the electronic excitation effects induced by low-energy ions,especially protons collisions.This paper employs first-principle molecular dynamics method to simulate the collision processes between the low-energy protons and the acetylene molecules,and investigates the electronic excitation effects of the acetylene molecules,the energy loss of the protons and the number of the excited electrons in the valence band of the target molecules in the collisions.Our studies reveal that the electronic excitation effect is the main mechanism for the electronic energy loss of the incoming ions,prove that the traditional linear theory model of the electronic stopping power can not describe the electronic energy loss of low-energy ions traversing molecule targets correctly and clarify the reasons for it.