Lei Zi-Ming

Charge exchange into excited states in collisions between noble gas ions and atoms

Experimental resutls obtained demonstrate that there are two processes of excitation in every collision system: one is an one-electron capture into excited states, the other is a direct excitation of projectile and target by projectile ion impact. From the comparison of the emission cross sections between the two collision systems, we find that the potential energy defect and the velocity of incident ion are very important factors in emission cross sections, and a competition process of these factors in collisions occurs.

A comparison of emission cross sections in collision between Ar+2 and Ne or He

There are three channels of excitation in collisions between Ar2+ and Ne or He, the first is double-electron capture into excited states, the second is single-electron capture into excited states and the third is direct excitation of target by the impact of incident ion. The emission cross sections of ArI, ArII, NeI, NeII, HeI and HeII lines have been obtained and compared. The emission cross sections of Ar2+ +Ne collision system is much larger than that of Ar2+ +He collision system.

A comparison of balmer α, β, γ emission in collisions between H1+, H2+, H3+ and He, Ne, Ar

Balmer α, β, γ emissions have been measured in collisions between H1+, H2+, H3+, and He, Ne, Ar in energy range of 50-150keV, using TN-1710 optical multichannel analysis system (OMA). The emission cross sections of Hα, Hβ, Hγ lines are given. The experimental results demonstrate that the emission cross sections of Hα,β,γ lines in H3+ +He, Ne, Ar collision systems are larger than those in H1+, H2+ +He, Ne, Ar, respectively.

Single and double electron capture into excited states in collisions between ions and neutrals

Recent experimental results on charge transfer into excited states in collisions between single and double charged ions with He, Ne, Ar, H2 and O2 are presented, respectively. Laboratory energy range of the ion beams of Heq+, Arq+, Ne+ (q=1,2)ions is (70-170)xq KeV. The optical measurement was performed by an optical multichannel analysis system (OMA).

Generation of UV radiation at 285.4nm by four-wave mixing in magnesium vapor

The generation of UV radiation at 285.4nm by four-wave mixing in magnesium vapor is reported. A dye-laser radiation is focused into magnesium vapor and tuned to the resonance wavelength of the two-photon transition 3s2 0S1 - 3s4s 0S1. The dependence of the signal intensity at 285.4nm on Mg vapor density and incident laser power has been measured and the spectral behaviour has been studied.