激光作用(艹屈)产生的正负离子的相关研究

LATIVE STUDIES OF POSITVE AND NEGATIVE IONS GENETED FROM CHRYSENE WITH LASER VAPORIZATION AND IONIZATION

以高能量密度的脉冲激光束作用于固体样品,可以产生信号强度相近的正负离子.最近我们在一台自制的激光等离子体源飞行时间质谱计上,首次实现了正负离子质谱的同时检测,并通过对稠环芳香烃——(艹屈)的研究,得到了一些有意义的发现.

The mass spectra of both positive and negative ions in laser plasma were recoded at first time in a self—built apparatus. The mass spectra produced from cyrysene with pulsed laser vaporization are introduced in this paper. By correlative studies of both positive and negative ions, it is found that the positive ions still keep the original cyclic configuration, but all negative ions become linear. In positive ion mass spectra, the quasi—molecular ions have overwhelming intensity, followed by the fragments with structure of phenathene. For the negative ions of lower mass, the ability of combining hydrogen atom with their end carbon atoms alternates according to the even/odd number of carbon atoms in the species.