Energy disposal in thermal-energy charge transfer reactions determined by kinetic energy measurements of product ions: Ne++O2→O++O+Ne and Ar++O2→O2++Ar

Abstract

The possibility of deducing reaction mechanisms from kinetic energy released in the products is discussed for thermal energy ion·molecule reactions. An experimental method based on ICR spectrometry is described, allowing for the first time kinetic energy measurements of ions produced in thermal energy reactions. Application to charge transfer from Ne+ and Ar+ to O 2 is presented. Ne+ produces 0+ ions with 0.55 eV mean KE, corresponding to the 0+(4S') + OeD) dissociation limit of oi, while Ar+ produces 0i' molecular ions with 1 eV mean KE corresponding to ground state ions in rather high vibrational states (V~ 8-10). With Ne+ the results can be accounted for in the framework of a (quasi) resonant charge transfer process while with Ar+ charge transfer involves electronic into kinetic energy transfer.

Unimolecular Decomposition in Ion Cyclotron Resonance Traps: Kinetic Energy Release and Microsecond-Scale Kinetics

“…The total energy of a fragment ion upon its formation is As the ions travel through an axial electrostatic potential P(z), an additional kinetic energy is acquired. The kinetic energy becomes T(z) = T 0 + P(0) -P(z) while the total energy is unchanged: E(z) = P(z) + T(z) = P(z) + T 0 + P(0) -P(z) = T 0 + P(0) = E 0 (12) When the DVT is activated, the potential P' is applied instantly to both trapping plates. Under this condition kinetic energy of the ion is unchanged but the total energy of the ion is increased by ∆P(z) = P´(z) -P(z), i.e.…”

“…Post-decomposition dynamics information can be recovered from the ion abundance due to the fact that electrostatic-field trapping in ICR-MS is directly effected by kinetic energy of the ions. 3 This approach has been widely used [9][10][11][12][13][14][15][16][17][18][19] to directly measure KERs, derive bimolecular rate constants and correct the kinetics based on the intrinsic relationship between trapping efficiency and ion kinetic energy. In the past, this method was called kinetic energy ion cyclotron resonance spectroscopy (KE-ICRS).…”

Parallel Spectral Acquisition with Orthogonal ICR Cells

“…In multisection ICR cells, ions are able to be drifted from cell to cell along [16–19] or perpendicularly [20–23] to the magnetic field lines. The drift ICR cells were generally used for the study of ion-molecule reaction.…”