Bond Dissociation Energy of F with Spectroscopic Accuracy Measured Using Predissociation and Threshold Fragment Yield Spectroscopy.

In this study, we conducted precise measurements to determine the bond dissociation energy of F, yielding a value of 12939.95 ± 0.40 cm 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(P) + F(P) 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 only. This enabled us to determine the bond dissociation energy of F with an uncertainty of 0.7 cm, which was further reduced to 0.4 cm using threshold fragment yield spectra of F(P). Consequently, the accuracy of the F bond dissociation energy now surpasses 0.5 cm, placing it with similar precision to those of N, O, and CO.