Song Cheng (Atomic Physics)

Associate Professor of Physics
Ph.D., 1991, Kansas State University


Experimental atomic collisions remain one of the most effective means to study the atomic structures and various corrections which modify the atomic structure at various degrees. While colliding partners cover almost all the elements in the periodic table, the most vigorous researches are focused on the few- electron atoms or their equivalent few-electron ions. These systems offer theoreticians a possibility to develop a detailed model to study the physical processes in atomic collisions.

During the collision, the electronic states of an atom and/or the vibrational and rotational states of a molecule change resulting in the change of charge state, momentum, energy level, and wave function. The frontier of experimental measurements of these quantities is a) to measure small momentum changes in both longitudinal and transverse directions; b) to pursue a higher energy resolution to resolve the finer energy levels and a wider energy range to enhance efficiency and accuracy; and c) to measure the lifetime in the order of picosecond to femtosecond which is impossible by a conventional technology.

R. Ali, I. Ahmad, H.G. Berry, R.W. Dunford, D.S. Gemmell, E.P. Kanter, P.H. Mokler, A.E. Livingston, S. Cheng and L.J. Curtis, "Spectral Distribution of the Two-Photon Decay of He-like Krypton," Nucl. Instr. Meth in Phys.Rev. B 98, 69-73 (1995).

A.E. Livingston, K.W. Kukla, C.M. Vogel Vogt, H.G. Berry, R.W. Dunford, D.S. Gemmell, E.P. Kanter, J. Suleiman, R. Ali, S.Cheng and L.J. Curtis, "Fine Structure Energies for the 1s2s3S - 1s2p3P Transition in Helium-Like Ions,"Nucl. Instr. Meth. in Phys. Rev. B 98, 28-32 (1995).

K.W. Kukla, A.E. Livingston, J. Suleiman, H.G. Berry, R.W. Dunford, D.S. Gemmell, E.P. Kanter, S. Cheng and L.J. Curtis, "Fine Structure Energies for the 1s2s3S-1s2p3P Transition in Helium-like Ar16+," Phys. Rev. A 51, 1905-17 (1995).

P.Ali, H.G. Gordon, S. Cheng, R.W. Dunford, H. Esbensen, D.S. Gemmerll, E.P. Kanter, T. Lebrun, L. Young and W. Bauer, "The Interaction of High-Energy, Hightly Charged Xe Ion with Buckyballs," Nuclear Instruments and Methonds in Physical Research B 96, 545 (1995).

Cheng, S., Cocke, C.L., Frohne, V., Kamber, E.Y., McGuire, J.H., and Wang, Y. 1993. Angular distribution of dissociated deuterons by MeV O8+ impact. Physical Review A 47:3923-3929.

Cheng, S., Dunford, R.W., Kanter, E.P., Berry, H.G., Gemmel, D.S., Zabransky, B.J., Livingston, A.E., Curtis, L.J., Bailey, J., and Nolen, J.A. 1993. Branching ratio for the M1 decay of the 2 2SŤ state in one-electron krypton. Phys. Rev. A 47:903-910.

Cheng, S., Dunford, R.W., Kanter, E.P., Berry, H.G., Gemmel, D.S., Zabransky, B.J., Livingston, A.E., and Curtis, L.J. 1993. Lifetime of the 22SŤ state in hydrogenlike krypton. The Physics of Highly Charged Ions. In AIP Conf. Proc 274:394-397.