Infrared spectrum of a protonated fluorescence dye: Acridine orange
| Autor: | Otto Dopfer, Anita Lagutschenkov |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Materials science
010405 organic chemistry Infrared Photodissociation Analytical chemistry Infrared spectroscopy Protonation 010402 general chemistry Mass spectrometry 01 natural sciences Atomic and Molecular Physics and Optics Fourier transform ion cyclotron resonance 0104 chemical sciences 13. Climate action Physics::Atomic and Molecular Clusters Infrared multiphoton dissociation Physical and Theoretical Chemistry Atomic physics Spectroscopy |
| Zdroj: | Journal of Molecular Spectroscopy. 268:66-77 |
| ISSN: | 0022-2852 |
| DOI: | 10.1016/j.jms.2011.03.024 |
| Popis: | The infrared (IR) spectrum of protonated acridine orange (AOH+) has been measured in the fingerprint range (600–1740 cm−1) by means of IR multiple photon dissociation (IRMPD) spectroscopy. The IRMPD spectrum of mass-selected AOH+ ions was recorded in a Fourier transform ion cyclotron resonance mass spectrometer equipped with an electrospray ionization source using an IR free electron laser. Quantum chemical calculations at the B3LYP and RI-MP2 levels of theory using the cc-pVDZ basis set were employed to guide the isomer and vibrational assignment of the measured IR spectrum. Protonation at the nitrogen atom of the central ring (N10) was predicted to be by far the most stable protonation site. Good agreement is observed between the IRMPD spectrum and the linear IR absorption spectrum of the N10 isomer calculated at the B3LYP level. The IRMPD spectrum exhibits 14 bands in the spectral range investigated, which are assigned to individual normal modes of N10. The fragmentation process of AOH+ upon IR activation in the ground electronic state is analyzed in some detail, revealing that elimination of CH4 is thermodynamically favored over loss of CH3NCH2. The effects of protonation on the geometric and electronic structure are revealed by comparison with neutral AO. Astrophysical implications of the IR spectrum of AOH+ are briefly discussed in the context of the unidentified IR emission bands. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect