No abstract

We measured the double-to-single-ionization ratios R of helium impacted by the intermediate velocity C 4+ ion and found that R decreases as 1/v. This type of velocity dependence is consistent with the data for very highly charged ions (N 7+ ∼ U 92+ ). The charge state and velocity dependences of R are interpreted well by the classical over-barrier-ionization (COBI) model. It is found that the ratio R can be written in a manner of R = 0.28 √ q/v for very high-q projectiles in the strong coupling (q/v > 1) regime. This theoretical prediction is in excellent agreement with extensive experimental data.

No abstract

Zou Xian-Rong( ), Liu Lan-Diao( ), Ji Ming-Chao( ),Feng Dong( ), Chen Xi-Meng( ), and Shao Jian-Xiong( )

No abstract