Accession Number : ADA299422
Title : Dications as High Energy Species: Graduate Training in Chemical Physics at JILA. Supplement.
Descriptive Note : Final rept. 30 Jun 92-30 Jun 95,
Corporate Author : COLORADO UNIV AT BOULDER
Personal Author(s) : Lineberger, W. C. ; Leone, S. R. ; Oneil, S. V.
PDF Url : ADA299422
Report Date : 30 JUN 1995
Pagination or Media Count : 2
Abstract : During the past year, ASSERT scholar Joseph Kim and graduate student Jim Smith have been working on the coaxial laser-ion spectrometer which had previously been utilized to elucidate the dissociation dynamics of dications. The thrust of his work has now changed, to emphasize studies of dynamics in ionic clusters where the cluster consists of a fuel oxidant and an ionic core. The first step in making this transition concerned efforts to produce cold ions and cluster ions in the coaxial beam machine. Mr. Kim has made major modifications to the ion source, installing a pulse supersonic expansion and a new electron beam system to enable the production of cold cluster ions. There have been a number of technical details associated with the production of cold ions which have slowed progress in the last year. There were many problems associated with electrical breakdown in the floating ion source and with collisional heating of the ions. All of these problems have now been solved, and we are able to produce cold cluster ions on a relatively routine basis. The best "thermometer" to characterize the ion source has proven to be the rotational temperature of OH(-). The first photodetachment spectra of OH(-) are being obtained by Mr. Kim at present, and he has already demonstrated surprisingly sharp photodetachment thresholds. It appears that the long range forces involved with the OH permanent dipole moment dramatically alter the photodetachment threshold law, greatly increasing the rate at which the cross section rises very near threshold. This sharp rise will be a very important diagnostic in the studies of the structure of cluster ions. jg p.2
Descriptors : *CATIONS, *HIGH ENERGY, LOW TEMPERATURE, PRODUCTION, PHOTOCHEMICAL REACTIONS, CHEMICAL DISSOCIATION, CHEMICALS, DYNAMICS, LASERS, FUELS, ELECTRON BEAMS, SPECTRA, CLUSTERING, PHYSICS, PULSES, HEATING, CROSS SECTIONS, OXIDIZERS, EXPANSION, SUPERSONIC CHARACTERISTICS, DISSOCIATION, BREAKDOWN(ELECTRONIC THRESHOLD), COLLISIONS, THERMOMETERS, ION SOURCES, FLOATING BODIES, DIPOLE MOMENTS.
Subject Categories : Physical Chemistry
Electrical and Electronic Equipment
Atomic and Molecular Physics and Spectroscopy
Distribution Statement : APPROVED FOR PUBLIC RELEASE