Studies of transition states and radicals by negative ion photodetachment

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1991

OSTI ID:5718877

Metz, R B

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[sup [minus]] anion provides a direct spectroscopic probe of the transition state region of the potential energy surface for the neutral hydrogen transfer reaction X + HY [yields] 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. The authors have used colinear adiabatic simulations of the photoelectron spectra to evaluate trial potential energy surfaces for the bimolecular reactions and have extended the adiabatic approach to three dimensions and used it to evaluate empirical potential energy surfaces for the I + HI and Br + HI reactions. In addition, the authors have derived an empirical, collinear potential energy surface for the Br + HBr reaction that reproduces experimental results and have extended this surface to three dimensions. Photodetachment of a negative ion can also be used to study neutral free radicals. The authors have studied the vibrational and electronic spectroscopy of CH[sub 2]NO[sub 2] by photoelectron spectroscopy of CH[sub 2]NO[sub 2][sup [minus]], determining the electron affinity of CH[sub 2]NO[sub 2], gaining insight on the bonding of the [sup 2]B[sub 1] ground state and observing the [sup 2]A[sub 2] excited state for the first time. Negative ion photodetachment also provides a novel and versatile source of mass-selected, jet-cooled free radicals. The authors have studied the photodissociation of CH[sub 2]NO[sub 2] at 270, 235, and 208 nm, obtaining information on the dissociation products by measuring the kinetic energy release in the photodissociation.

• Research Organization: California Univ., Berkeley, CA (United States)
• OSTI ID: 5718877
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
400500* -- Photochemistry
ANIONS
BROMINE
BROMINE COMPOUNDS
CHARGED PARTICLES
CHEMISTRY
DISSOCIATION
ELECTRON SPECTROSCOPY
ELEMENTS
ENERGY
ENERGY LEVELS
EXCITED STATES
HALOGEN COMPOUNDS
HALOGENS
HYDRIODIC ACID
HYDROBROMIC ACID
HYDROGEN COMPOUNDS
INORGANIC ACIDS
IODINE
IODINE COMPOUNDS
IONS
MATHEMATICAL MODELS
NONMETALS
PHOTOCHEMISTRY
PHOTOELECTRON SPECTROSCOPY
POTENTIAL ENERGY
RADICALS
REACTION INTERMEDIATES
SPECTROSCOPY
VIBRATIONAL STATES