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Updated: Jul 5, 2025
06:53
Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F−
Published on: July 27, 2018
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Absolute Photoionization Cross Section and Dissociative Ionization Pathways of Alpha-Pinene
Ryan Rodriguez1, Craig A Taatjes2, Giovanni Meloni1,3
1Department of Chemistry, University of San Francisco, San Francisco, CA 94117, USA.
Summary
This study presents the first absolute photoionization cross section for alpha-pinene (AP), a key monoterpenoid. It also details relative cross sections for its fragments, aiding atmospheric chemistry research.
Area of Science:
- * Atmospheric Chemistry
- * Physical Chemistry
- * Molecular Spectroscopy
Background:
- * Alpha-pinene (AP) is a prevalent monoterpenoid with significant atmospheric implications.
- * Understanding AP photoionization is crucial for atmospheric modeling and aerosol formation studies.
- * Limited experimental data exists for AP photoionization cross sections.
Purpose of the Study:
- * To determine the absolute photoionization cross section of alpha-pinene (AP).
- * To measure the relative photoionization cross sections of AP's dissociative fragments.
- * To investigate the appearance energies and pathways of dissociative ionization.
Main Methods:
- * Multiplexed vacuum ultraviolet (VUV) synchrotron photoionization (PI) mass spectrometry.
- * Experiments conducted in the 8.0–11.0 eV photon energy range.
- * Theoretical calculations using the G4 level of theory.
Main Results:
- * The absolute photoionization cross section for parent AP at 11.0 eV was measured as 17±4 Mb.
- * Total ionization cross section at 11.0 eV was determined to be 92±23 Mb.
- * Dissociative fragments were identified at m/z 121, 94, 93, 92, and 80.
Conclusions:
- * This work provides the first experimental absolute photoionization cross section for alpha-pinene.
- * The data offers critical insights into AP's behavior under VUV irradiation.
- * Findings contribute to more accurate atmospheric chemistry models and aerosol research.
Keywords:
adiabatic ionization energyalpha-pinenemultiplexed synchrotron photoionization mass spectrometryphotoionization cross sectionsMore Related Videos
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