title: Realistic modeling of ion-neutral collisions in quadrupole ion traps.
abstract: In this study, three ion-neutral collision models have been discussed and compared, including the Langevin, the hard-sphere and the mixed collision models. With the pseudo-potential approximation, analytical expressions of ion secular motions with the hard-sphere and mixed collision models have been obtained for the first time. Through numerical simulations and theoretical calculations, it is found that the mixed collision model could be used as a general description of ion-neutral collisions under different conditions. Langevin collision model is a good description of low energy collisions between small ions and neutrals, while hard-sphere collision model could be used to describe high energy collisions and/or ions with higher masses (larger physical sizes). These analytical expressions of ion motion decay profiles enable the creation of direct relationships between time-domain image currents with ion collision cross sections.
authors.affiliation: School of Life Science, Beijing Institute of Technology, Beijing, 100081, China.
authors.forename: Muyi
authors.initials: M
authors.lastname: He
authors.forename: Dan
authors.initials: D
authors.lastname: Guo
authors.forename: Yan
authors.initials: Y
authors.lastname: Feng
authors.forename: Xingchuang
authors.initials: X
authors.lastname: Xiong
authors.forename: Huzhong
authors.initials: H
authors.lastname: Zhang
authors.forename: Xiang
authors.initials: X
authors.lastname: Fang
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
keywords: Langevin collision model; hard-sphere collision model; image current; ion collision cross section; ion-neutral collision; mixed collision model