Photoelectron-photoion coincidence momentum imaging for dissociative ionization in intense laser fields

光電子光イオン同時計測運動量画像法を用いた強レーザー場中における解離性イオン化

穂坂 綱一; 板倉 隆二; 横山 啓一  ; 山内 薫*; 横山 淳

Hosaka, Koichi; Itakura, Ryuji; Yokoyama, Keiichi; Yamanouchi, Kaoru*; Yokoyama, Atsushi

強レーザー場中の分子は複雑に競合するさまざまな解離性イオン化経路を持つ。イオン化で生成する電子状態と解離経路の相関を明らかにするために、光電子光イオン同時計測運動量画像観測装置を開発した。この装置をエタノールの解離性イオン化に適用し、光電子の運動量画像が同時計測される解離イオン種に強く依存することを見いだした。

When molecules are exposed to intense laser fields, dissociative ionization is efficiently induced and several decomposition pathways competes. The present study aims at revealing the correlation between the electronic states just after ionization and the following dissociation process. The photoelectron-photoion coincidence momentum imaging (PEPICO-MI) technique enables us to detect photoelectrons and photoions produced in a single event simultaneously. We applied PEPICO-MI to dissociative ionization of ethanol (CHOH), whose branching ratio varies as a function of the laser pulse duration. When ethanol molecules are irradiated with a short laser pulse, photoelectron images strongly depend on the correlated product ions.