Production of a rovibrationally selected O2+beam for dissociative recombination studies

A Dochain,X Urbain,I.F Schneider,O Dulieu,J Robert

doi:10.1051/epjconf/20158405001

A Dochain, X Urbain + Show 3 more

Open Access

https://doi.org/10.1051/epjconf/20158405001

Copy DOI

Journal: EPJ web of conferences	Publication Date: Jan 1, 2015
Citations: 6	License type: cc-by

Affiliation: Université Catholique de Louvain

Abstract

In order to study the reactivity of particular excited states of O2+, we have studied the resonance enhanced multiphoton ionization of O2 via the 1,3Πg states with a frequency-doubled pulsed dye laser in the range 296.5–303.5 nm. We managed to produce a large ensemble of O2+ ions in selected v+,N+ states, with v+ = 0 or 1, and N+ up to 25. Such an ion source, with tunability and selectivity of the output rovibrational state, can be coupled to a storage device in order to study the collisional and radiative properties of infrared inactive species.

Highlights

The dissociative recombination (DR) of O+2 has been extensively studied, for its contribution to the green airglow [1], and its sensitivity to vibrational excitation [2]
In order to study the reactivity of particular excited states of O+2, we have studied the resonance enhanced multiphoton ionization of O2 via the 1,3 g states with a frequencydoubled pulsed dye laser in the range 296.5–303.5 nm
We have successfully shown that a rovibrationally selected O+2 beam may be produced by (2+1) resonance enhanced multiphoton ionization (REMPI)

Summary

Introduction

The dissociative recombination (DR) of O+2 has been extensively studied, for its contribution to the green airglow [1], and its sensitivity to vibrational excitation [2]. The Rydberg character of that intermediate state ensures the conservation of the vibrational quantum number upon ionization, while rotation may only be affected by the angular momentum imparted to the photoelectron. In this case, we chose the O2(d 1 g) Rydberg state associated to the ground state of the ion. Rovibrational state selectivity was verified experimentally, using in the first case a simulation of the wavelength-dependent ion yield for a close comparison to the experimental spectrum, and in the second case by measuring the kinetic energy release (KER) upon dissociative charge transfer with an effusive potassium jet

Experimental setup

Intermediate state

Nuclear spin effect

Selection rules

Line shape and intensity

Rovibrational selectivity of the REMPI process

Conclusion