A Quasiclassical trajectory calculation to compute the reaction cross section and thermal rate constant for the cesium exchange reaction CsI + Cs Cs + ICs

擬古典的トラジェクトリー計算によるセシウム交換反応CsI+CsCs+ICsの反応断面積及び反応速度定数の計算

小林 孝徳*; 松岡 雷士*; 横山 啓一  

Kobayashi, Takanori*; Matsuoka, Leo*; Yokoyama, Keiichi

セシウムの同位体分離法の開発に関連して、ヨウ化セシウム分子とセシウム原子の衝突によるセシウム交換反応の反応速度定数を量子化学計算及び擬古典トラジェクトリー計算により評価した。その結果、3.610cm/molecule/sという大きな値が得られた。また、わずかながら正の温度依存性を持つことが示され、長距離相互作用による引力ポテンシャルと解離プロセスの影響がその原因と考えられた。

One of important research targets in the development of cesium isotope separation system is design of recovery process of cesium atom. Relevant to this research target, the reaction cross section and reaction rate constant of a cesium exchange reaction through collision of the cesium iodide molecules with cesium atoms are calculated by a quasi-classical trajectory calculation based on a potential energy surface obtained by quantum chemistry calculations. Consequently, the rate constant is calculated to be 3.6 10 cmmolecules, as large as collision rate in the present condition. In addition, slightly positive temperature dependence is observed in the rate constant. This behavior is explained with the long-range attractive force and effect of subsequent dissociation process.