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Atomic and Molecular Physics Group (Ma Group)

Institute of Modern Physics (IMP), Chinese Academy of Sciences (CAS)

The research fields mainly cover ion/electron-atom/molecule collision dynamics, precision dielectronic recombination spectroscopy of highly charged ions, and atomic laser spectroscopy.

The experimental works were carried out at the heavy ion cooler storage ring (CSR) and the 320 kV platform for multiple disciplinary research with highly charged ions in Lanzhou. DR experiments of 36, 40Ar15+, 40Ca17+, 40Ar14+, 40Ca16+, 40Ar13+, 56Fe17+, 58Ni19+, and 112Sn35+ HCSs were carried out, and the absolute DR rates as well as plasma rates were obtained. A series of benchmark data were collected which could be applied in the studies of plasma and astrophysics.

As for charge exchange processes, angular differential cross sections and state-resolved cross sections for single electron capture, double electron capture, transfer ionization of highly charge ions with atoms were measured with/without excitation of target ions in the velocity range of 0.3 to 2 a.u. Molecule fragmentation induced by electron and ion impact were identified and the fragmentation mechanisms were studied. Fragmentation / dissociation of charged atomic / molecular dimers due to Inter atomic/molecular Coulombic Decay, Radiative Charge Transfer, or proton transfer were investigated, and the results are very helpful for understanding the radiation damages of the environment effects in tissues induced by energetic particles.

In addition, the group investigating the strong Coulomb coupling effect, which plays an important role to understand in astrophysics, warm dense matter, and inductively coupled plasmas, by taking the electron spectroscopy and laser spectroscopy of the ultracold plasma from the photoionization of the cold atoms in a magneto-optical trap.


Xinwen MA
Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 73000, China
Group Website
Phone: +86 931 4969 346

  • [1] S. Xu et al., "Damaging Intermolecular Energy and Proton Transfer Processes in Alpha-Particle-Irradiated Hydrogen-Bonded Systems", Angewandte Chemie International Edition 57, 17023-17027 (2018). [link to article]
  • [2] L. Dou et al., "Theoretical investigation of electron-ion recombination processes of Li-like tungsten ions", Journal of Quantitative Spectroscopy and Radiative Transfer 220, 162-171 (2018). [link to article]
  • [3] S. X. Wang et al., "Electron–ion Recombination Rate Coefficients of Be-like 40Ca16+", The Astrophysical Journal 862, 134 (2018). [link to article]
  • [4] Y. Gao et al., "Probing scattering phases via two-center interferences in collisions of He2+ on CO", Physical Review A 97, 020701 (2018). [link to article]
  • [5] Z. K. Huang et al., "Dielectronic and Trielectronic Recombination Rate Coefficients of Be-like Ar14+", The Astrophysical Journal Supplement Series 235, 2 (2018). [link to article]
  • [6] S. Yan et al., "Interatomic relaxation processes induced in neon dimers by electron-impact ionization", Physical Review A 97, 010701 (2018). [link to article]
  • [7] Y. Gao et al., "Fully differential study of few-body dynamics in multi-electron atomic fragmentation processes", Journal of Physics B: Atomic, Molecular and Optical Physics 50, 10LT01 (2017). [link to article]
  • [8] R. T. Zhang et al., "Single-electron capture in 3-keV/u Ar8+-He collisions", Physical Review A 95, 042702 (2017). [link to article]
  • [9] D. L. Guo et al., "State-selective electron capture in 30- and 100-keV He+ + He collisions", Physical Review A 95, 012707 (2017). [link to article]
  • [10] X. Ma et al., "HIAF: New opportunities for atomic physics with highly charged heavy ions", Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 408, 169-173 (2017). [link to article]
  • [11] X. Zhu et al., "Probing the geometry of Ar2N2 cluster by 1 MeV Ne8+ ions", Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 408, 42-45 (2017). [link to article]


Charge-Exchange Processes Crossed Beams Dielectronic Recombination Electron – Ion Collisions Highly Charged Ions Ion Beams Ion Storage Ring Merged Beams Tungsten