Electron capture rates in collisions of H(+) ions with Si atoms: Capture by the ground and excited state

Abstract

A theoretical investigation for charge transfer in collisions of H(+) ions with neutral Si atoms both in ground and metastable states at collision energies from 0.001 eV to 10 keV was carried out. The adiabatic potential curves of SiH(+) were obtained by employing the multireference single- and double-excitation configuration interaction (MRD-CI) method. A semi-classical molecular orbital expansion method with a straight line trajectory of the incident ion was employed to study the collision dynamics. A fully quantum mechanical representation of the molecular orbit expansion method was employed for collision energies below 30 eV. The coupled equations were solved numerically to obtain the scattering matrix. The charge transfer cross section below 10 keV was obtained. Because of a small asymptotic energy defect between the initial and closest electron capture channels, and because of the exothermicity in nature for the transition, the electron capture process from the ground state (sup 3)P Si atoms was extremely efficient.

0.001eVから10keVの衝突エネルギーにおける水素陽イオンと基底状態、準安定状態の中性ケイ素原子間の衝突における電荷移動について理論的研究を行った。SiH(+)の断熱ポテンシャル曲線を多参照単、2重励起配置相互作用(MRD-CI)法を用いて求め、入射イオン直線軌道による半古典的分子軌道展開法を用いて衝突動力学を解明した。30eV以下の衝突エネルギーでは分子軌道展開法の完全な量子力学的表記法を用いた。結合方程式を数値計算によって解き散乱行列を求めた。10keV以下の電荷移動断面積を求めた。初期および最近接電子捕獲チャンネル間の僅かな漸近的エネルギー欠損、および遷移の発熱性により、ケイ素原子(sup 3)Pの基底状態における電子捕獲過程は極度に効果的であった。