Electron photodetachment from transient negative ions in the multiphoton ionization of CH3I

1985 ◽  
Vol 82 (11) ◽  
pp. 4880-4885 ◽  
Author(s):  
William A. Chupka ◽  
Anne M. Woodard ◽  
Steven D. Colson ◽  
Michael G. White
Keyword(s):  
Multiphoton Ionization ◽  
Negative Ions ◽  
Electron Photodetachment

scholarly journals Mass-resolved electronic circular dichroism ion spectroscopy

Science ◽  
2020 ◽  
Vol 368 (6498) ◽  
pp. 1465-1468 ◽  
Author(s):  
Steven Daly ◽  
Frédéric Rosu ◽  
Valérie Gabelica
Keyword(s):  
Circular Dichroism ◽  
Three Dimensional ◽  
Polarized Light ◽  
Negative Ions ◽  
Data Interpretation ◽  
Electronic Circular Dichroism ◽  
Circularly Polarized Light ◽  
Chiral Compounds ◽  
Electron Photodetachment ◽  
Circular Dichroïsm

DNA and proteins are chiral: Their three-dimensional structures cannot be superimposed with their mirror images. Circular dichroism spectroscopy is widely used to characterize chiral compounds, but data interpretation is difficult in the case of mixtures. We recorded the electronic circular dichroism spectra of DNA helices separated in a mass spectrometer. We studied guanine-rich strands having various secondary structures, electrosprayed them as negative ions, irradiated them with an ultraviolet nanosecond optical parametric oscillator laser, and measured the difference in electron photodetachment efficiency between left and right circularly polarized light. The reconstructed circular dichroism ion spectra resembled those of their solution-phase counterparts, thereby allowing us to assign the DNA helical topology. The ability to measure circular dichroism directly on biomolecular ions expands the capabilities of mass spectrometry for structural analysis.

Spectrometric Characterization of Purified C60 and C70

1990 ◽  
Vol 206 ◽  
Author(s):  
Keith R. Lykke ◽  
Michael J. Pellin ◽  
Peter Wurz ◽  
Dieter M. Gruen ◽  
Jerry E. Hunt ◽  
...  
Keyword(s):  
Electronic Absorption ◽  
Mass Spectra ◽  
Fluorescence Spectra ◽  
Multiphoton Ionization ◽  
Negative Ions ◽  
Picosecond Laser ◽  
Laser Desorption ◽  
Signal To Noise ◽  
Neutral Species

ABSTRACTC60 and C70 were synthesized and purified according to published procedures. Both nanosecond and picosecond laser desorption from coated substrates gave copious positive and negative ions. Mass spectra (TOF and FTMS) with excellent signal to noise, showing only the C60 and C70 mass peaks, have been observed. Well-resolved isotopic structure was seen in the FTMS spectra in agreement with the natural abundance of carbon. Laser desorption and multiphoton ionization/photodissociation of the neutral species, as well as electronic absorption, FTIR, and fluorescence spectra, have been obtained.

scholarly journals Theory of multiphoton ionization tested on negative ions

1992 ◽  
Vol 45 (3) ◽  
pp. 2116-2117 ◽  
Author(s):  
Theodoros Mercouris ◽  
Cleanthes A. Nicolaides
Keyword(s):  
Multiphoton Ionization ◽  
Negative Ions

Electron photodetachment spectroscopy of trapped negative ions

1987 ◽  
Vol 87 (3) ◽  
pp. 607-622 ◽  
Author(s):  
Donna M. Wetzel ◽  
John I. Brauman
Keyword(s):  
Negative Ions ◽  
Electron Photodetachment
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