Supersonic cooling of short-lived molecular states in a pulsed microcavity plasma jet

"Electronic states of helium diners having potential energy > 24 eV and radiative lifetimes as short as 19 ns have been generated in a micro-plasma jet at super-atmospheric pressure and rotationally cooled by supersonic expansion. Spatial-temporal spectrograms of d^3Σ+u→(b^3)π_g (v', v"") = (0, 0) emission are obtained, which contain the information about the dynamic cooling process during the molecular beam expansion. Analysis shows the spatial-temporal evolution of the rotational temperature to be a damped sinusoid that reaches a minimum value of 100 K, which is attributed to the reflection of electrons from a virtual cathode located downstream of the jet nozzle. Data fitting to the damped sinusoid function yields a spatially-averaged electron density of 10^8 cm^(-3). The experimental setup has the potential to be used in exploration of the spectroscopy and plasma dynamics in various gas molecules."

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Electrical & Computer Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2016

Author dc:creator

• Su, Rui

Contributors dc:contributor

• Eden, James G.

• microplasma
• supersonic cooling
• molecular spectroscopy

Statement dc:rights

• Copyright 2016 Rui Su

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/90736

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/90736