Reference Label Details
Ruscic 1990B. Ruscic and J. Berkowitz, J. Chem. Phys. 93, 5586-5593 (1990)
Photoion-Pair Formation and Photoelectron-Induced Dissociative Attachment in C2H2: D0(HCC-H)
note C2HRuscic 1990 report an abrupt IPF threshold at 759 +- 1 A = 16.335 +- 0.021 eV. The mid-rise is no more than 1 A higher in energy, probably only 0.5 A (which would lead to about 16.346 eV as the desired threshold, which is within the quoted uncertainty). Ruscic 1990 also report the reshold for C2H2 + e- -> C2H2- -> H + C2H-, where the electron comes from direct ionization C2H2 -> C2H2+ + e- at the same energy. If treated as an appearance potential, the extrapolated threshold 880.5 A = 14.081 eV at xxx K, and with an estimated field correction for a linear threshold of 0.030 eV becomes 14.111 eV. However, they also note that the threshold is temperature-invariant and give the half-rise as 876.5 (+- 0.5) A = 14.145 +- 0.008 eV. While in the final analysis they opt for the average of the two with a larger uncertainty (878.5 +- 2 A), the half-rise point approach seems more appropriate.