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Title: Studies of transition states and radicals by negative ion photodetachment

Abstract

Negative ion photodetachment is a versatile tool for the production and study of transient neutral species such as reaction intermediates and free radicals. Photodetachment of the stable XHY - anion provides a direct spectroscopic probe of the transition state region of the potential energy surface for the neutral hydrogen transfer reaction X + HY → XH + Y, where X and Y are halogen atoms. The technique is especially sensitive to resonances, which occur at a specific energy, but the spectra also show features due to direct scattering. We have used collinear adiabatic simulations of the photoelectron spectra to evaluate trail potential energy surfaces for the biomolecular reactions and have extended the adiabatic approach to three dimensions and used it to evaluate empirical potential energy surfaces for the I + Hl and Br + HI reactions. In addition, we have derived an empirical, collinear potential energy surface for the Br + HBr reaction that reproduces our experimental results and have extended this surface to three dimensions. Photodetachment of a negative ion can be also used to study neutral free radicals. We have studied the vibrational and electronic spectroscopy of CH 2NO 2 by photoelectron spectroscopy of CH 2NO 2 -,more » determining the electron affinity of CH 2NO 2, gaining insight on the bonding of the 2B 1 ground state and observing the 2A 2 excited state for the first time. Negative ion photodetachment also provides a novel and versatile source of mass-selected, jet-cooled free radicals. We have studied the photodissociation of CH 2NO 2 at 270, 235, and 208 nm, obtaining information on the dissociation products by measuring the kinetic energy release in the photodissociation.« less

Authors:
 [1]
  1. Univ. of California, Berkeley, CA (United States)
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
10158344
Report Number(s):
LBL-31878
ON: DE92017011
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: TH: Thesis (Ph.D.); PBD: Dec 1991
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANIONS; PHOTOELECTRON SPECTROSCOPY; ADIABATIC PROCESSES; COMPUTERIZED SIMULATION; RADICALS; REACTION INTERMEDIATES; HYDROGEN TRANSFER; POTENTIAL ENERGY; EXCITED STATES; HALOGEN COMPOUNDS; NITRO COMPOUNDS; 400201; CHEMICAL AND PHYSICOCHEMICAL PROPERTIES

Citation Formats

Metz, Ricardo Baer. Studies of transition states and radicals by negative ion photodetachment. United States: N. p., 1991. Web. doi:10.2172/10158344.
Metz, Ricardo Baer. Studies of transition states and radicals by negative ion photodetachment. United States. https://doi.org/10.2172/10158344
Metz, Ricardo Baer. Sun . "Studies of transition states and radicals by negative ion photodetachment". United States. https://doi.org/10.2172/10158344. https://www.osti.gov/servlets/purl/10158344.
@article{osti_10158344,
title = {Studies of transition states and radicals by negative ion photodetachment},
author = {Metz, Ricardo Baer},
abstractNote = {Negative ion photodetachment is a versatile tool for the production and study of transient neutral species such as reaction intermediates and free radicals. Photodetachment of the stable XHY- anion provides a direct spectroscopic probe of the transition state region of the potential energy surface for the neutral hydrogen transfer reaction X + HY → XH + Y, where X and Y are halogen atoms. The technique is especially sensitive to resonances, which occur at a specific energy, but the spectra also show features due to direct scattering. We have used collinear adiabatic simulations of the photoelectron spectra to evaluate trail potential energy surfaces for the biomolecular reactions and have extended the adiabatic approach to three dimensions and used it to evaluate empirical potential energy surfaces for the I + Hl and Br + HI reactions. In addition, we have derived an empirical, collinear potential energy surface for the Br + HBr reaction that reproduces our experimental results and have extended this surface to three dimensions. Photodetachment of a negative ion can be also used to study neutral free radicals. We have studied the vibrational and electronic spectroscopy of CH2NO2 by photoelectron spectroscopy of CH2NO2-, determining the electron affinity of CH2NO2, gaining insight on the bonding of the 2B1 ground state and observing the 2A2 excited state for the first time. Negative ion photodetachment also provides a novel and versatile source of mass-selected, jet-cooled free radicals. We have studied the photodissociation of CH2NO2 at 270, 235, and 208 nm, obtaining information on the dissociation products by measuring the kinetic energy release in the photodissociation.},
doi = {10.2172/10158344},
url = {https://www.osti.gov/biblio/10158344}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1991},
month = {12}
}

Thesis/Dissertation:
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