纳秒激光诱导C_(60)分子碎裂中轻碎片离子C_n^+(n<30)的产生机理研究  

Formation mechanisms of small fragment ions in nanosecond laser induced fragmentation of C_(60)

作　　者：钱东斌[1] 马新文[1] 张大成[1] 祖凯玲[1] 刘惠萍[1] 汶伟强[1] 

机构地区：[1]中国科学院近代物理研究所,兰州730000

出　　处：《物理学报》2008年第9期5810-5816,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10605034);国家自然科学基金重点项目(批准号:10434100)资助的课题~~

摘　　要：采用飞行时间质谱计测量了纳秒激光诱导C60分子碎裂中轻碎片离子Cn+(n≤11)的初始平均动能,结果显示轻碎片离子具有相同的初始平均动能(约为0.34 eV),并且该动能在一定范围内不随激光通量的变化而明显改变.结合前人的实验结果,对纳秒激光诱导C60分子碎裂中轻碎片离子Cn+(n<30)的主要产生模式作了新的阐述,即C60分子级联发射15个C2分子和一个电子形成自身不稳定的C3+0离子,在皮秒时间尺度内C3+0离子的笼形结构塌陷,进而轻碎片离子产生.The time of flight mass spectrometric technique was used to determine the initial mean kinetic energy of small fragment ions Cn^＋ （ n ≤ 11 ） produced from C60 excited by 532 nm nanosecond laser pulses. The measured kinetic energy shows little variation with the fragment mass and the laser fluence in a broad range. Based on the assumption that C30^＋ is produced predominantly by a single electron emission followed by successive C2 evaporation from hot C60 in the nanosecond laser field, the formation of small fragments is interpreted as the complete breakup of the unstable C30^＋ cage structure. The interpretation is consistent with the previously observed results.

关 键 词：飞行时间质谱计 轻碎片离子 笼形结构塌陷 初始动能 

分 类 号：O613.71[理学—无机化学]