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Updated: Jun 5, 2025

Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F−
Published on: July 27, 2018
Bond Dissociation Energy of F2 with Spectroscopic Accuracy Measured Using Predissociation and Threshold Fragment
Peng Wang1, Shiyan Gong1, Yuxiang Mo1
1Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China.
Abstract:
In this study, we conducted precise measurements to determine the bond dissociation energy of F2, yielding a value of 12939.95 ± 0.40 cm-1 or 154.7962 ± 0.0048 kJ/mol. Our research addresses this currently debated benchmark parameter crucial in thermochemistry and quantum chemistry. By analyzing a rotationally resolved spectrum of an ion-pair state close to the threshold of F(2P3/2°) + F(2P3/2) in the energy region of 14.6 eV, we made a significant observation. We discovered two neighboring rotational states with and without predissociation to the channel, exhibiting an energy spacing of 1.4 cm-1 only. This enabled us to determine the bond dissociation energy of F2 with an uncertainty of 0.7 cm-1, which was further reduced to 0.4 cm-1 using threshold fragment yield spectra of F(2P3/2). Consequently, the accuracy of the F2 bond dissociation energy now surpasses 0.5 cm-1, placing it with similar precision to those of N2, O2, and CO.
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