Fundamental Excitations of the Shared Proton in the H₃O₂^- and H₅O₂⁺ Complexes

Abstract

We exploit recent advances in argon predissociation spectroscopy to record the spectroscopic signature of the shared proton oscillations in the H3O2- system and compare the resulting spectrum with that of the H5O2+ ion taken under similar conditions. Very intense 1 <-- 0 transitions are observed below 1100 cm(-1) in both cases and are surprisingly sharp, with the 697 cm(-1) transition in H3O2- being among the lowest in energy of any shared proton system measured to date. The assignments of the three fundamental transitions associated with the three-dimensional confinement of the shared proton in H3O2- are carried out with full-dimensional (DMC) calculations to treat this strongly anharmonic vibrational problem.

Can the Four-Coordinated, Penta-Valent Oxygen in Hydroxide Water Clusters Be Detected through Experimental Vibrational Spectroscopy?

“…4,16,27,53,54 To consider if these simulations do have an experimental connection, we consider here two different kinds of experiments that are presently being employed by many groups to understand these kinds of clusters. In one set of experiments, 12 an argon tagged cluster is isolated using mass-spectrometry and then irradiated using a single IR photon of a given frequency. The photon energy, if absorbed, induces the cluster to undergo intracluster vibrational redistribution which may result in a suitable amount of energy being transferred into the argoncluster weak interaction and the subsequent ejection of argon.…”

Experimental and Ab Initio Dynamical Investigations of the Kinetics and Intramolecular Energy Transfer Mechanisms for the OH + 1,3-Butadiene Reaction between 263 and 423 K at Low Pressure

“…Such a shift in the frequency is to be distinguished from the large number of OH stretch red shifts that have been recently reported in the literature for hydrogen-bonded systems. [61][62][63][72][73][74] While in all of those cases it was the hydroxyl proton that was involved through active hydrogen bonding leading to a shift in frequency, in the case of isoprene-OH, it is the lone pair electrons associated with the oxygen, the donation of which to nearby protons leads to a red shift. These ring formations, as we note in the next section, are also responsible for energy transfer from the OH and CO stretch modes into the various CH bend and wag modes of the adduct molecules.…”

IR Spectrum of the H5O2+ Cation in the Context of Proton Disolvates L−H+−L

“…For the very strong base OH -in the H 3 O 2 -ion, the ν as OHO stretching frequency for the bare anion is 697 cm -1 . 57 This suggests that the stronger is the base, the lower should be ν as OHO. However, as shown earlier in Figures 6 and 7 To understand this apparent contradiction, we return to the effect of structural asymmetry in H 5 O 2 + ion on the ν as OHO frequency.…”