Frankowski Marcin, Sun Zheng, Smith-Gicklhorn Alice M
Institut für Physikalische und Theoretische Chemie, Technische Universität München, Lichtenbergstr. 4, D-85747 Garching, Germany.
Phys Chem Chem Phys. 2005 Mar 7;7(5):797-805. doi: 10.1039/b415412f.
The positive molecular ions of astrophysical interest--protonated and fragment ions of acetonitrile are investigated by means of mass-selective deposition in Ne matrices and FT-IR spectroscopy in the region of 500-4000 cm(-1). Ionic species are generated by electron impact ionization with parallel fragmentation and) ion-molecule reactions of an acetonitrile precursor, CH3CN (CD3CN). The ions are deposited in Ne matrices together with an excess of electrons to prevent a buildup of space charge. Spectral assignments are supported by deuterium isotopic measurements and by density functional (DFT/B3LYP) computations. This work resulted in the spectral characterization of protonated acetonitrile CH3CNH+, as well as the identification of three cationic cyanomethyl C2H2N+ isomers: H2CCN+, H2CNC+ and HCCNH+. Although the spectral assignments for two ionic isomers, H2CCN+ and H2CNC+, are somewhat tentative, experimental results give rather strong evidence for the occurrence of the linear HCCNH+ ion.
通过在氖基质中进行质量选择沉积以及在500 - 4000厘米⁻¹区域进行傅里叶变换红外光谱，研究了具有天体物理学意义的正分子离子——乙腈的质子化离子和碎片离子。离子物种通过电子碰撞电离与乙腈前体CH₃CN（CD₃CN）的平行碎片化和离子 - 分子反应产生。离子与过量电子一起沉积在氖基质中，以防止空间电荷的积累。光谱归属得到氘同位素测量和密度泛函（DFT/B3LYP）计算的支持。这项工作得到了质子化乙腈CH₃CNH⁺的光谱表征，以及三种阳离子氰甲基C₂H₂N⁺异构体的鉴定：H₂CCN⁺、H₂CNC⁺和HCCNH⁺。尽管对于两种离子异构体H₂CCN⁺和H₂CNC⁺的光谱归属有些不确定，但实验结果为线性HCCNH⁺离子的存在提供了相当有力的证据。
