Spectroscopy of transient neutral species via negative ion photoelectron spectroscopy

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

OSTI ID:5720165

Weaver, A

Negative ion photoelectron spectroscopy has been used to study two types of transient neutral species: bound free radicals (NO[sub 2] and NO[sub 3]) and unstable neutral species ([IHI] and [FH[sub 2]]). The negative ion time-of-flight photoelectron spectrometer used for these experiments is described in detail. Photoelectron spectra of NO[sub 2][sup [minus]] at 266 and 213 nm show the [anti X] ([sup 2]A[sub 1]), [anti A]([sup 2]B[sub 2]) and [anti C]([sup 2]A[sub 2]) bands of NO[sub 2]. The author obtains the energy of the [anti A]([sup 2]B[sub 2]) state as T[sub o] = 1.204 eV from Franck-Condon simulations of the vibrational structure, and the energy of the [anti C]([sup 2]A[sub 2]) state as T[sub o] = 2.02 eV. Photoelectron spectra of NO[sub 3][sup [minus]] at 266 nm show the [sup 2]A[sub 2] band of NO[sub 3]. Franck-Condon forbidden transition to odd quanta of a non-totally symmetric mode ([nu][sub 4]) appear in the spectra and are attributed to second-order linear (pseudo-Jahn-Teller) coupling between the [sup 2]A[sub 2] and [sup 2]E states via the degenerate [nu][sub 4] mode. Spectra at 213 nm also show the [open quotes]dark[close quotes] [sup 2]E state 0.868 eV above the ground state. The transition state region of the potential energy surface for a neutral bimolecular reaction, A + BC, can be studied by photodetachment of the corresponding stable anion, ABC[sup [minus]], provided that the geometry of ABC[sup [minus]] is similar to that at the neutral transition state. Spectra of IHI[sup [minus]] and IDI[sup [minus]] at 266 nm show evidence of long-lived quasi-bound states of the neutral [IHI] complexes. Photoelectron spectra of FH[sub 2][sup [minus]], FD[sub 2][sup [minus]] and FDH[sup [minus]] also show evidence of quasi-bound states.

• Research Organization: California Univ., Berkeley, CA (United States)
• OSTI ID: 5720165
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ANIONS
CHALCOGENIDES
CHARGED PARTICLES
DEUTERIUM COMPOUNDS
ELECTRON SPECTROSCOPY
ENERGY
ENERGY LEVELS
EXCITED STATES
FLUORINE COMPOUNDS
FRANCK-CONDON PRINCIPLE
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
INELASTIC SCATTERING
IODINE COMPOUNDS
IONS
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
POTENTIAL ENERGY
RADICALS
REACTION INTERMEDIATES
RESONANCE SCATTERING
SCATTERING
SPECTROMETERS
SPECTROSCOPY
TIME-OF-FLIGHT METHOD
TIME-OF-FLIGHT SPECTROMETERS
VIBRATIONAL STATES