摘要
用Ｐｅｎｎｉｎｇ型离子阱经碰撞反应Ｈ２＋＋Ｈ２→Ｈ４＋产生稳定的Ｈ４＋。主要的反应产物是 Ｈ３＋，但十分明显地观测到Ｈ４＋信号。Ｈ４＋在阱中稳定存在时间长达 ０．１ｓ量级。远比 Ｋｉｒｃｈｎｅｒ等人测 量的１０－６ｓ量级长。最后讨论了生成Ｈ４＋的反应过程机制。
A Penning ion trap was used to generate H4+ by reaction H2+ +H2at very low pressures. The original H2+ were produced by electron impact. Subseqently reaction occurred. The dominant reaction product was H3+ but a significant H4+ signal was observed at suitable H2 pressure and delay time interval. Statistical mean energy of the H2+ was about 0.65eV. It is found that the reaction H2+ +H2→ H3+ +H probability is large at low energy (≤ 1 eV). As a reslut, the mojority of the H2+ transformed to H3+. Only very small proportion of reaction products was stable intermediate H4+. Because the depth of H4+ potential energy surface minimum is very shallow, only the H2+ with very slow velocity can probably react with H2 to produce stable H4+. The proportion of H3+ to H4+ was about 4: 1 from our experimental data. It is estimated by statistical distribution law that the H2+ with low energy less than 0.4eV can probably form stable H4+ species. Because H4+ signal occurred after long delay time (i.e. trapping interval), it is positively concluded that the H4+ were formed by reaction H2+ +H2→ H4+. The trapping interval is of the order of 0.1 s. Any quasibound H4+ would have decayed at times short relative to 0.1s and hence the H4+ signal corresponds to stable H4+. It is much longer than order of 10-6s measured before by Kirchner.
