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| Reference Label |
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| Taniguchi 1999 | N. Taniguchi, K. Takahashi, Y. Matsumi, S. M. Dylewski, J. D. Geiser, and P. L. Houston, J. Chem. Phys. 111, 6350-6355 (1999)
Determination of the Heat of Formation of O3 using Vacuum Ultraviolet Laser-Induced Fluorescence Spectroscopy and Two-Dimensional Product Imaging Techniques | | note O3d | Taniguchi 1999 report three experiments: one PHOFEX and two 2D fragment imaging. The PHOFEX shows an onset of 309.45 +- 0.03 nm = 32315.4 +- 3.1 cm-1 = 386.58 +- 0.04 kJ/mol, which is, as noted by the authors, somewhat higher (78.1 cm-1 or 0.93 kJ/mol) than the similar experiment of Takahashi 1997. Two 2D imaging experiments were performed, one at 305.746 nm and one at 309.096 nm. From these, they report 386.59 +- 0.03 kJ/mol and 386.62 +- 0.05 kJ/mol. However, their analysis seems to be using non-existent rotational levels of O2 (a 1Deltag) corresponding to J=1 and 0. From these three values they derive a consensus value of 386.59 +- 0.04 kJ/mol and use the same nu00 and E(O2, 1D2) as Takahashi 1997 (see note O3c) to derive D0(O3) = 102.48 +- 0.04 kJ/mol. If the PHOFEX experiment is interpreted in the same manner as Takahashi 1997 in note O3c, it produces 8555.5 +- 3.1 cm-1 = 102.35 +- 0.04 kJ/mol. Assuming that the two 2D imaging results refer to J=0, they need to be increased by 8.507 cm-1, yielding 32324.9 +- 2.5 cm-1 and 32327.4 +- 4.2 cm-1. Proceeding as with the PHOFEX experiment yields 8565.0 +- 2.5 cm-1 = 102.46 +- 0.03 kJ/mol and 8567.5 +- 4.2 cm-1 = 102.49 +- 0.05 kJ/mol. The two 2D imaging results clearly agree with each other. The PHOFAX experiment can be also brought into better agreement by assuming that the onset refers to the hypothetical J=0 level of O2(a 1Deltag), and hence needs to be inreased by 8.507 cm-1 = 0.10 kJ/mol, yielding 102.45 +- 0.04 kJ/mol. In that case the consensus value appears to be 102.46 +- 0.04 kJ/mol, which - because of cancellation of errors - is only 0.02 kJ/mol lower than their original value. |
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