Scaling rules for the ionization of biological molecules by highly charged ions

Proton-impact-induced electron emission from biologically relevant molecules studied with a screened independent atom model

We use the recently introduced independent-atom-model pixel counting method to calculate proton-impact net ionization cross sections for a large class of biologically relevant systems including pyrimidines, purines, amino acids, and nucleotides from 10 keV to 10 MeV impact energy. Overall good agreement with experimental data, where available, is found. A scaling prescription that involves coefficients derived from the independent atom model is shown to represent the cross section results better than scalings based on the number of (bonding) valence electrons of the target molecules. It is sho…

On the Generation of Multiply Charged Argon Ions in Nanosecond Laser Field Ionization of Argon

Zhang and coworkers have recently reported results of experiments involving irradiation of argon clusters doped with bromofluorene chromophores by nanosecond-long pulses of 532 nm laser light. Multiply-charged ions of atomic argon (charge states, n, up to 7) and carbon (charge states up to 4) are observed which are sought to be rationalised using an evaporation model. The distinguishing facet of exploding clusters being progenitors of energetic ions and electrons constitutes the key driver for contemporary research in laser-cluster interactions; it is, therefore, important to point out inconsi…

Ionization of biological molecules by multicharged ions using the stoichiometric model

In the present work, we investigate the ionization of molecules of biological interest by the impact of multicharged ions in the intermediate to high energy range. We performed full non-perturbative distorted-wave calculations (CDW) for thirty-six collisional systems composed by six atomic targets: H, C, N, O, F, and S -which are the constituents of most of the DNA and biological molecules- and six charged projectiles (antiprotons, H, He, B, C, and O). On account of the radiation damage caused by secondary electrons, we inspect the energy and angular distributions of the emitted electrons from…

MAICRM : A general model for rapid simulation of hot dense plasmas

We propose a general model, Multi-Average Ion Collisional-Radiative Model (MAICRM), to rapid simulate the ionization and population distributions of hot dense plasmas. In MAICRM, the orbital occupation numbers of ions at the same charge stage are averaged and determined by the excitation and de-excitation processes; the populations of the average ions are determined by the ionization and recombination processes with the fixed orbital average occupation numbers in each ion. The calculated mean ionizations and charge state distributions of MAICRM are in general agreement with the other theoretic…

超短脉冲laser辐射下生物材料中中性粒子的速度分布

Velocity distribution of neutral particles ejected from biological material under ultra short laser radiation

利用激光后电离飞行时间质谱技术研究了超短脉冲激光烧蚀生物材料时中性粒子的喷射。可以证明，除了电离物质之外，还有大量的中性粒子被喷射出来。通过记录中性粒子飞行时间质谱作为烧蚀和后电离脉冲之间的延迟时间的函数，进行烧蚀羽流的时间研究。在烧蚀阈值附近，喷射机制主要是机械性质的，由激光诱导压力的弛豫驱动。在这种应力约束状态下，喷射导致非常宽的速度分布和极低的速度。

利用混合阱探测稀化超冷$^7$Li气体中的缔合电离

Associative ionization in a dilute ultracold $^7$Li gas probed with a hybrid trap

本研究利用离子-原子混合阱探测超冷$^7$Li气体中的缔合电离过程，明确了Li$_2^+$与Li$^+$的生成及转化机制，揭示了超冷稀化气体中共振激发引发的重要分子动力学过程。