纳秒强激光电离苯产生高价碳离子的波长效应

随着高强度超短脉冲激光器的发展 ,分子、原子与强激光场的相互作用已经成为一个重要的研究领域 ,其中分子或原子团簇在强场下发生的库仑爆炸现象成为研究的热点之一 .苯具有高对称的环形结构 ,激发态能级密集 ,因此 ,不论是早期的激光对分子的多光子电离解离 (MPID) ,以及强场与多原子分子的相互作用 ,还是后来超短脉冲激光下团簇相关的库仑爆炸研究都将其作为一个重要的研究对象1- 8] .最近 ,我们用波长为 5 3 2nm、脉宽为 2 5ns的激光对苯等物质进行电离时 ,发现在 1 0 10 ～1 0 11W/cm2 的功率密度下 ,其质谱中出现了高平动能的C2 +…

Wavelength Dependence of Production of Multicharged Carbon Ions in Nanosecond Intense Laser Ionization of Seeded Benzene Beam

The photoionization of seeded benzene beam by 25 ns laser pulse at wavelengths of 266, 355 and 1064 nm has been studied by the time-of-flight mass spectrometry. The observed mass spectra at 266 nm and 355 nm at intensities of 10^10-10^11 W/cm^2 indicate a multiphoton ionization and dissociation (MPID) process, in which C^+ C2Hx^+, C3Hx^+ , C4Hx^+ and C6H6^+ are main products. While at 1064 nm laser of similar intensities, the domain ion is C^4+ which is produced from Coulomb explosion. The longer wavelength facilities the energy absorption rate during inverse bremsstrahlung, which leads to the resulting wavelength dependence of the muhicharged atomic ions.