Open Access. Powered by Scholars. Published by Universities.®

Social and Behavioral Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

2011

Series

Faculty of Science - Papers (Archive)

Spectroscopy

Articles 1 - 3 of 3

Full-Text Articles in Social and Behavioral Sciences

Electron Affinities, Well Depths, And Vibrational Spectroscopy Of Cis- And Trans-Hoco, Christopher J. Johnson, Michael E. Harding, Berwyck L. J Poad, John F. Stanton, Robert E. Continetti Jan 2011

Electron Affinities, Well Depths, And Vibrational Spectroscopy Of Cis- And Trans-Hoco, Christopher J. Johnson, Michael E. Harding, Berwyck L. J Poad, John F. Stanton, Robert E. Continetti

Faculty of Science - Papers (Archive)

We report vibrationally resolved photoelectron spectra of internally cold HOCO– and DOCO– anions at wavelengths near and well above the detachment threshold. These spectra are dominated by a strong Franck–Condon progression of three low-energy modes of the cis isomer, the first gas-phase measurement of these vibrations. Using highly resolved, near-threshold spectra we are able to reassign the electron affinities (EAs) of cis- and trans-HOCO to 1.51 ± 0.01 and 1.37 ± 0.01 eV, respectively. Using these EAs, well depths with respect to OH + CO are determined to be 1.07 ± 0.02 eV for trans-HOCO and 0.99 ± 0.02 eV …


Photoelectron-Photofragment Coincidence Spectroscopy In A Cryogenically Cooled Linear Electrostatic Ion Beam Trap, Christopher J. Johnson, Ben B. Shen, Berwyck L. J Poad, Robert E. Continetti Jan 2011

Photoelectron-Photofragment Coincidence Spectroscopy In A Cryogenically Cooled Linear Electrostatic Ion Beam Trap, Christopher J. Johnson, Ben B. Shen, Berwyck L. J Poad, Robert E. Continetti

Faculty of Science - Papers (Archive)

A cryogenically cooled linear electrostatic ion beam trap for use in photoelectron-photofragment coincidence (PPC) spectroscopy is described. Using this instrument, anions created in cold, low-dutycycle sources can be stored for many seconds in a ∼20 K environment to cool radiatively, removing energetic uncertainties due to vibrationally excited precursor anions. This apparatus maintains a well-collimated beam necessary for high-resolution fragment imaging and the high experimental duty cycle needed for coincidence experiments. Ion oscillation is bunched and phase-locked to a modelocked laser, ensuring temporal overlap between ion bunches and laser pulses and that ions are intersected by the laser only when travelling …


Remote Sensing Of Atmospheric Trace Gases By Ground-Based Solar Fourier Transform Infrared Spectroscopy, Clare Paton-Walsh Jan 2011

Remote Sensing Of Atmospheric Trace Gases By Ground-Based Solar Fourier Transform Infrared Spectroscopy, Clare Paton-Walsh

Faculty of Science - Papers (Archive)

The changing composition of the earth’s atmosphere is a matter of intense scientific research as we strive to understand details of the physical and chemical mechanisms that control our climate. Fourier transform spectroscopy has been applied very successfully to the study of trace gases in the atmosphere by examining terrestrial atmospheric absorption lines in the infrared spectrum from the Sun. In fact many gases were first discovered in the atmosphere during the 1940’s from their absorption features in the infrared solar spectrum. These early optical absorption measurements of the atmosphere using the Sun as a source were made with grating …