Negative Ion Formation in Hydrogen Peroxide and Water Vapor. The Perhydroxide Ion.

Abstract

The negative ions formed by electron bombardment in water vapor and in a mixture of water and hydrogen peroxide vapors have been investigated in a mass spectrometer. The principal ions found with water vapor in the ion source are H~, 0~and OH-. With the addition of a small amount of hydrogen peroxide vapor, Oí -and ,ions are also found at relatively high intensity. No H2O2-(or 0-H20) ions were observed in either case. Data are presented to show that the OHion is formed in a secondary collision between Hand H20. Measurements of the total scattering cross-sections for 350 e.v. O,and O2H-ions in oxygen have been made. It is shown from these measurements that the ions of mass 32 obtained by the electron bombardment of oxygen are the same as those obtained from the H2O-H2O2 vapor. The utility of the scattering technique for the identification of gaseous ions is discussed.

Chemistry of Dissociated Water Vapor and Related Systems

“…Similar interference from decomposition products had been encountered by others (114, 130). Muschlitz and Bailey (160) have studied the mass spectra of water vapor and mixtures of water and hydrogen peroxide vapors. With water vapor H~, 0~, and OHwere the principal ions detected, but Oíand 02H_ ions appeared upon addition of small amounts of hydrogen peroxide vapor.…”

Reactant ions in negative ion plasma chromatography

“…This is to be compared to 0.010 Torr-1 obtained from the data of Pack and Phelps (37) for a total pressure of 45 Torr, 7.25 Torr-1 for an unspecified temperature from the data of Moruzzi Cluster solvation reactions involving the 02~a nd the OH" ions have been studied by Arshadi and Kebarle (38) between 1 and 5 Torr. The associative cluster reactions (H20)"02-+ , + 02(or N2) -(H20)"tl02-+ 02(or N2) (30) (H20)"OH-+ H20 + 02(or N2) -(H20)"tlOH-+ 02(or N2) (31) are third order while the dissociative reactions (H20)n02-+ 02(or N2) -(H20)r.,02-+ H20 + 02(or N2) (32) (H20)rOH--h 02(or N2) -(H20)r.iOH-+ H20 + 02(or N2) (33) are second order. Writing the van't Hoff relation in the form log = j X 103 -B…”

Dissociative electron attachment in nanoscale ice films: Thickness and charge trapping effects

“…The low-energy DEA resonances in gas-phase water molecules are well characterized. [12][13][14][15][16][17][18][19][20][21][22][23][24][25] Three distinct states produce H Ϫ (D Ϫ ) at incident electron energies below 15 eV. The 2 B 1 , 2 A 1 , and 2 B 2 core-excited Feshbach resonances correspond to states having two 3s:4a 1 electrons and a hole in the 1b 1 , 3a 1 , or 1b 2 orbital, respectively.…”

“…The DEA process in gas-phase water molecules has been investigated in great detail, and the excitations that re-sult in anion production are well known. [12][13][14][15][16][17][18][19][20][21][22][23][24][25] Water vapor supports three low-energy, core-excited Feshbach DEA resonances, all of which lead to the production of H Ϫ (D Ϫ ), O Ϫ , and OH Ϫ (OD Ϫ ), with H Ϫ (D Ϫ ) being the predominant anion formed. When water is condensed onto a Pt substrate or on top of a noble gas layer, all three DEA resonances are observed to produce H Ϫ (D Ϫ ) ions, at electron energies of ϳ7, 9, and 11 eV.…”