A combined zero electronic kinetic energy spectroscopy and ion-pair dissociation imaging study of the F2+(XΠg2) structure

Abstract

Rotationally resolved pulsed field ionization and zero electronic kinetic energy photoelectron spectra for the transition F(2) (+)(X (2)Pi(g))<--F(2)(X (1)Sigma(g) (+)) have been recorded using the extreme ultraviolet coherence radiation. The vibrational energy spacings, rotational constants, and spin orbit coupling constants for the first three vibrational states of F(2) (+)(X (2)Pi(g)) have been determined accurately. The first adiabatic ionization potential (IP) of F(2) is determined as IP(F(2))=126 585.7+/-0.5 cm(-1). To determine the threshold E(tipp) for ion-pair production of F(2), the images of F(-)((1)S(0)) in the velocity mapping conditions have also been recorded at the photon energy of 126 751 cm(-1). Taking the Stark effect into account, the E(tipp) is determined as E(tipp)(F(2))=126 045+/-8 cm(-1) (15.628+/-0.001 eV). By combing the IP(F(2)) and the E(tipp)(F(2)) determined in this work and together with the reported ionization potential and electronic affinity of the F atom, the bond dissociation energies of F(2) and F(2) (+) are determined as D(0)(F(2))=1.606+/-0.001 eV and D(0)(F(2) (+))=3.334+/-0.001 eV, respectively.

Active Thermochemical Tables: dissociation energies of several homonuclear first-row diatomics and related thermochemical values

“…F -), which was obtained by velocity mapping the F -fragment. When combined with the generally accepted values for the ionization energy and electron affinity of F atom, it produced D 0 (F 2 ) = 154.96 ± 0.10 kJ/ mol; this value was subsequently slightly lowered in an erratum [78] However, from the perspective of the ATcT approach, establishing beforehand which of the possibilities is correct is not a crucial issue at all. Arbitrating between mutually inconsistent determinations is one of the things that the ATcT approach is explicitly designed to do: as long as there are sufficient alternate thermochemical cycles in the TN, errant determination(s) will be identified during the ATcT analysis and brought into consistency with the rest of the TN by augmenting their uncertainties.…”

“…Since the introduction of the ion-pair threshold of Yang et al [77,78] into the TN a number of versions ago (using their original uncertainty of ±8 cm -1 or ±0.09 6 kJ/mol), the ATcT analysis consistently finds this determination to be problematic, unless the original uncertainty is increased by approximately a factor of 3.6, to ± 0.34 4 kJ/mol. Other than it being inconsistent with the remaining knowledge content of the TN (where the latter consists of the cumulative knowledge of well over a thousand related determinations, vide infra), it is unclear at this point what exactly may be the problem with the threshold of Yang et al or with its original uncertainty.…”

“…Yang et al [77] have reported the ion-pair formation threshold of F 2 (corresponding to the process F 2 ? F ?…”

Investigation of superexcited states in molecular deuterium

“…The high resolution XUV/VUV (extreme ultra violet/vacuum ultra violet) laser [18][19][20][21][22][23][24] used in experiment is a new tool for investigation of the fine details of spectroscopy and dynamics of molecular superexcited states.…”

“…[21][22][23][24]. Briefly, the coherent XUV radiation was generated by using the resonance-enhanced four-wave mixing inside a pulsed Kr jet in a XUV monochromator chamber equipped with a gold coated toroid grating.…”