Rare gas alkali ionic excimers

The rare gas alkali ionic molecules are established as a new class of ionic excimers which emit in the vacuum ultraviolet (VUV) regime of the electromagnetic spectrum. Temporal and spectral characteristics of these species with (XeRb)$\sp{+}$ at 164 nm and (XeCs)$\sp{+}$ at 160 nm have been investigated by soft x-ray excitation in a laser-produced plasma and by high energy pulsed electron beam pumping in this work. Soft x-ray pumping of XeF(B $\to$ X) and (XeRb)$\sp{+}$ yielded the first observation of excimer molecules formed by reactive kinetics in a laser-produced plasma. The spectrum of (XeRb)$\sp{+}$ was observed. The spectral structure could be assigned to 3 dipole allowed transitions originating from the 0$\sp{+}$(II), 1(II), 1(I) upper states ending in the 0$\sp{+}$(I) ground state. A kinetic study of electron beam pumped mixtures of Ar/Xe/Rb and Ar/Xe/Cs was performed. The observed temporal decays of (XeRb)$\sp{+}$ and (XeCs)$\sp{+}$ were analyzed. The results suggest that electron deactivation is surprisingly not a dominant quenching process for rare gas alkali ions. The radiative lifetimes are 150 $\pm$ 50 ns for (XeCs)$\sp+$ and 250 $\pm$ 50 ns for (XeRb)$\sp+$. In addition several quenching rate constants were extracted from the experimental results. These rate constants and lifetimes were incorporated into a kinetic model for these species. This kinetic model reproduced the experimental observations well providing the electron quenching rate coefficient is kept to a maximum of 5 $\times$ 10$\sp{-9}$ cm$\sp3$s$\sp{-1}$. Estimates for the upper state densities were computed using this model to be $\sim$4 $\times$ 10$\sp{15}$ cm$\sp{-3}$ for (XeCs)$\sp+$ and 2 $\times$ 10$\sp{15}$ cm$\sp{-3}$ for (XeRb)$\sp+$. Including absorption due to the photoionization of the alkali atoms, the net gain coefficients are computed to be on the order of 10$\sp{-2}$ cm$\sp{-1}$. Therefore the rare gas alkali ionic excimers appear to be a promising class of candidates as storage media for VUV lasers.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Engineering

Grantor

Rice University

Year dc:date.issued

1990

Author dc:creator

• Millar, Pamela S.

Advisor dc:contributor.advisor

• Sauerbrey, Roland A.

• Molecular physics
• Optics
• Radiation

Statement dc:rights

• Copyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/1911/16370

OAI identifier oai:identifier

oai:repository.rice.edu:1911/16370