On the multielectron dissociative ionization of some cyclic aromatic molecules induced by strong laser fields

被引:34
作者
Tzallas, P
Kosmidis, C
Ledingham, KWD
Singhal, RP
McCanny, T
Graham, P
Hankin, SM
Taday, PF
Langley, AJ
机构
[1] Univ Ioannina, Dept Phys, Atom & Mol Phys Lab, GR-45110 Ioannina, Greece
[2] Univ Glasgow, Dept Phys & Astron, Glasgow G12 8QQ, Lanark, Scotland
[3] Rutherford Appleton Lab, Cent Laser Facil, Didcot OX11 0QX, Oxon, England
关键词
D O I
10.1021/jp001096m
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The interaction of strong laser fields (4 x 10(16) W/cm(2)) with cyclic aromatic molecules (furan, pyrrole, pyridine, and pyrazine) has been studied at lambda = 790 nm. The fragmentation processes of multiply charged transient molecular ions were analyzed by means of a time-of-flight (TOF) spectrometer. Most ion peaks consisted of one broad and one sharp component. From the analysis of the peak profiles the kinetic energies of the molecular and atomic fragment ions have bean measured. On the basis of these energy values and the estimated charge separation distances, it is concluded that, for furan, it is probable that Coulomb explosion takes place in multiple charged parent ions with deformed molecular structure. The doubly charged parent ions of furan and pyrrole fragments through charge separation processes. At higher charged transient parent ions the fragmentation proceeds through direct (instantaneous) process. Moreover, there is evidence that, at least for furan, the ionization process takes place via a direct field ionization mechanism. Pyridine and pyrazine multiple charged ions seem to follow different dissociation routes. The abundance ratios C+/A(+) (A = N, O) for the singly charged atoms were found to be equal to the stoichiometric ratio for all the molecules studied, while a divergence has been observed for the C-2,C-3+/A(2,3+) (A = N, O) ratios.
引用
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页码:529 / 536
页数:8
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