title: Optical and X-ray emission spectroscopy of high-power laser-induced dielectric breakdown in molecular gases and their mixtures.
abstract: Large-scale plasma was created in molecular gases (CO, CO2, N2, H2O) and their mixtures by high-power laser-induced dielectric breakdown (LIDB). Compositions of the mixtures used are those suggested for the early earth's atmosphere of neutral and/or mildly reducing character. Time-integrated optical spectra emitted from the laser spark have been measured and analyzed. The spectra of the plasma generated in the CO-containing mixtures are dominated by emission of both C2 and CN radicals. A vibrational temperature of approximately 10(4) K was determined according to an intensity distribution in a vibronic structure of the CN (B2Sigma(+)u-X2Sigma(+)g) violet band. For comparison, the NH3-CH4-H2-H2O mixture has been irradiated as a model of the strongly reducing version of the early earth's atmosphere. In this mixture, excited CN seems to be significantly less abundant than C2. The LIDB experiments were in the molecular gases carried out not only in the static cell but also using a large, double stream pulse jet (gas puff target) placed in the vacuum interaction chamber. The obtained soft X-ray emission spectra indicate the presence of highly charged atomic ions in the hot core of high-power laser sparks.
authors.affiliation: J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejskova 3, 182 23 Prague 8, Czech Republic.
authors.forename: Dagmar
authors.initials: D
authors.lastname: Babankova
authors.forename: Svatopluk
authors.initials: S
authors.lastname: Civis
authors.forename: Libor
authors.initials: L
authors.lastname: Juha
authors.forename: Michal
authors.initials: M
authors.lastname: Bittner
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Cihelka
authors.forename: Miroslav
authors.initials: M
authors.lastname: Pfeifer
authors.forename: Jirí
authors.initials: J
authors.lastname: Skala
authors.forename: Andrzej
authors.initials: A
authors.lastname: Bartnik
authors.forename: Henryk
authors.initials: H
authors.lastname: Fiedorowicz
authors.forename: Janusz
authors.initials: J
authors.lastname: Mikolajczyk
authors.forename: Leszek
authors.initials: L
authors.lastname: Ryć
authors.forename: Tereza
authors.initials: T
authors.lastname: Sedivcova