塩酸の氷触媒によるイオン化

K Bolton¹, J B Pettersson

¹Contribution from the School of Engineering, University College of Borås, SE-501 90, Borås, Sweden.

Journal of the American Chemical Society

|July 27, 2001

まとめ

塩酸 (HCl) は,上層圏の氷の表面で容易にイオン化し,これはオゾン層の減少に不可欠な急速なプロセスです. この表面イオン化メカニズムは,観測された実験結果を説明し,平流圏の化学に影響を与えます.

科学分野:

大気化学大気化学
物理化学物理化学
環境科学環境科学

背景:

ストラトスフィアのオゾン層の減少は,重大な環境問題である.
氷の粒子が平流層の化学,特にオゾン層の劣化に果たす役割は,現在調査中です.
氷上の塩酸 (HCl) のイオン化は,提案された重要なステップです.

研究の目的:

ストラトスフィアの氷粒子のHClイオン化のメカニズムを調査する.
氷の表面でのHClイオン化のエネルギー的可行性を決定する.
このイオン化メカニズムが平流層のオゾン層の減少に及ぼす影響を評価する.

主な方法:

Ab initio計算は,モデルHCl-水クラスタを使用して行われました.
イオン化過程を研究するために計算モデルが採用されました.
理論的な計算により,氷の表面でのHClイオン化のエネルギーバリアを評価した.

主要な成果:

氷の表面でのHClイオン化は,障壁のないプロセスです.
提案されたメカニズムは迅速で,露出したクロライドアニオンを生成します.
この結果は,低温での氷上のHClイオン化の実験的観測と一致しています.

結論:

高層圏の氷の上に存在するHClの表面イオン化は,簡単で迅速なプロセスです.
このメカニズムは,平流層のオゾン層の減少に大きく寄与している可能性が高い.
発見は既存の理論を補完し,実験データと一致しています.

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