电子诱导氯二氟乙酸（CClF2COOH）分子纳滤膜中的反应：碎片阴离子的解吸和 CO2 的形成。

Electron induced reactions in molecular nanofilms of chlorodifluoroacetic acid (CClF2COOH): desorption of fragment anions and formation of CO2.

机构信息

Institut für Chemie und Biochemie-Physikalische und Theoretische Chemie Freie, Universität Berlin, Takustrasse 3, D-14195 Berlin, Germany.

出版信息

J Chem Phys. 2010 Nov 21;133(19):194503. doi: 10.1063/1.3505550.

DOI:10.1063/1.3505550

PMID:21090864

Abstract

Electron induced reactions in molecular nanofilms of chlorodifluoroacetic acid (CClF(2)COOH) are studied by electron stimulated desorption (ESD) of fragment anions and temperature programed thermal desorption spectroscopy (TDS). The fragment anions O(-), F(-), OH(-), and Cl(-) are formed from broad resonance features in the energy range of 4-14 eV and assigned to dissociative electron attachment (DEA) of molecules or dimers at or near the surface of the film, followed by desorption. The strong low energy DEA resonances (0-2 eV) observed in a previous gas phase study [J. Kopyra et al., Int. J. Mass. Spectrom. 285, 131 (2009)] are completely suppressed in ESD. Electron irradiation at energies above 10 eV results in the formation of CO(2), as revealed by TDS. The extended irradiation of a 3 ML film (25 nA, 240 min) results in a nearly completely transformation of the initial compound in favor of CO(2) and other by-products.

摘要

电子诱导反应在氯二氟乙酸（CClF₂COOH）的分子纳滤膜中通过碎片阴离子的电子刺激解吸（ESD）和程序升温热解吸光谱（TDS）进行研究。碎片阴离子 O^-、F^-、OH^-和 Cl^-是从能量范围为 4-14 eV 的宽共振特征中形成的，并归因于薄膜表面或附近的分子或二聚体的离解电子附加（DEA），随后解吸。在先前的气相研究中观察到的强低能 DEA 共振（0-2 eV）[J. Kopyra 等人，Int. J. Mass. Spectrom. 285, 131 (2009)]在 ESD 中完全被抑制。在能量高于 10 eV 的电子辐照下，通过 TDS 揭示了 CO₂的形成。对 3 ML 膜（25 nA，240 min）的扩展辐照导致初始化合物几乎完全转化为 CO₂和其他副产物。