Photodetachment threshold spectroscopy of jet-cooled negative ions

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1992

OSTI ID:7112304

Kobayashi, T

Spectroscopy of ions and radicals is difficult primarily because attainable concentrations, especially of negative ions, are very low. In order to study negative ions and neutral radicals, a time-of-flight, photodetachment threshold spectrometer has been developed. This consists of a Corona Excited Supersonic Expansion ion source, a time-of-flight mass spectrometer with a reflectron, and a YAG pumped dye laser. The first half of this dissertation is devoted to the description of the apparatus, while the second half describes its application to ion spectroscopy. The main advantage of the current apparatus results from the production of rotationally cold ions by the nozzle expansion. This simplifies molecular spectroscopy enormously. The photodetachment threshold method can deal with low ion concentrations to provide information on both negative ions and their corresponding neutrals. Precise spectroscopic quantities, such as electron affinities and rotational constants, can be determined. Hydroxide anion, OH[sup [minus]], has been chosen as the first target negative ion. The photodetachment cross section spectrum of rotationally cold OH[sup [minus]] has been measured and is presented here along with absolute photodetachment cross sections of OH[sup [minus]] and the electron affinity of OH. Anomalous rotational threshold behavior has been observed, and this is discussed. Other results include absolute photodetachment cross section measurements of O[sub 2][sup [minus]], methoxide anion, CH[sub 3]O[sup [minus]], and ethoxide anion, C[sub 2]H[sub 5]O[sup [minus]].

• Research Organization: Oregon Univ., Eugene, OR (United States)
• OSTI ID: 7112304
• Country of Publication: United States
• Language: English

Related Subjects

664200* -- Spectra of Atoms & Molecules & their Interactions with Photons-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ALKOXY RADICALS
ANIONS
CHARGED PARTICLES
ELECTRONIC STRUCTURE
ENERGY LEVELS
ETHOXY RADICALS
EXCITED STATES
HYDROXYL RADICALS
ION SPECTROSCOPY
IONS
LASER SPECTROSCOPY
METHOXY RADICALS
PEROXY RADICALS
RADICALS
ROTATIONAL STATES
SPECTROSCOPY