N-吡啶鎓阳离子的紫外光解离作用光谱

Ultraviolet photodissociation action spectroscopy of the N-pyridinium cation.

作者信息

Hansen Christopher S, Blanksby Stephen J, Chalyavi Nahid, Bieske Evan J, Reimers Jeffrey R, Trevitt Adam J

机构信息

School of Chemistry, University of Wollongong, NSW 2522, Australia.

Central Analytical Research Facility, Queensland University of Technology, QLD 4000, Australia.

出版信息

J Chem Phys. 2015 Jan 7;142(1):014301. doi: 10.1063/1.4904267.

DOI:10.1063/1.4904267

PMID:25573555

Abstract

The S1←S0 electronic transition of the N-pyridinium ion (C5H5NH(+)) is investigated using ultraviolet photodissociation (PD) spectroscopy of the bare ion and also the N2-tagged complex. Gas-phase N-pyridinium ions photodissociate by the loss of molecular hydrogen (H2) in the photon energy range 37,000-45,000 cm(-1) with structurally diagnostic ion-molecule reactions identifying the 2-pyridinylium ion as the exclusive co-product. The photodissociation action spectra reveal vibronic details that, with the aid of electronic structure calculations, support the proposal that dissociation occurs through an intramolecular rearrangement on the ground electronic state following internal conversion. Quantum chemical calculations are used to analyze the measured spectra. Most of the vibronic features are attributed to progressions of totally symmetric ring deformation modes and out-of-plane modes active in the isomerization of the planar excited state towards the non-planar excited state global minimum.

摘要

利用裸离子以及N₂标记配合物的紫外光解离（PD）光谱，对N - 吡啶鎓离子（C₅H₅NH⁺）的S1←S0电子跃迁进行了研究。在37,000 - 45,000 cm⁻¹的光子能量范围内，气相N - 吡啶鎓离子通过失去分子氢（H₂）发生光解离，通过结构诊断性离子 - 分子反应确定2 - 吡啶鎓离子为唯一的共产物。光解离作用光谱揭示了振动电子细节，借助电子结构计算，支持了以下提议：在内部转换后，解离通过基态电子态上的分子内重排发生。量子化学计算用于分析测量光谱。大多数振动电子特征归因于完全对称的环变形模式以及平面激发态向非平面激发态全局最小值异构化过程中活跃的面外模式的进展。