Characterization of elusive neutrals and ions by neutralization-reionization mass spectrometry

Miscellaneous · Wed Jan 01 00:00:00 EST 1992

OSTI ID:5651061

Fura, A

Neutralization-reionization mass spectrometry (NRMS) provides a dilute gas phase environment where a variety of neutral species can be produced and characterized. In NRMS fast neutrals are produced from mass-selected precursor ions. The neutrals can undergo isomerization or dissociation by using a low ionization-energy target for neutralization or by angular resolution. The neutrals are reionized to positive or negative ions that are mass analyzed and detected. Angular resolution is used here to obtain NR spectra of isomeric butenes and N-hexenes. A study of oxirane produced an energy surface of five isomers, showing C-C favored over C-O bond rupture. [center dot]CH[sub 2]CH[sub 2]O[center dot], [sup +]CH[sub 2]CH[sub 2]O[center dot], and the oxirane cation represent bound structures, as do [center dot]CH[sub 2]CH[sub 2]O[sup [minus]], [sup [minus]][center dot]C(H)OCH[sub 3], and [sup [minus]][center dot]C(OH)CH[sub 3]. Protonation of ethanol produces two isomeric forms, the ion CH[sub 3]CH[sub 2]OH[sub 2][sup +] and a proton bound complex. A stable hypervalent neutral CH[sub 3]CH[sub 2]OH[sub 2] can be formed under non-thermalized conditions, while the neutral counterpart of the latter isomer is unstable. Small neutral and ionic carbon clusters have been studied by neutralization of the corresponding mass-selected cations and by ab initio calculations. Attempts to prepare different C[sub 4][sup +] and C[sub 4] isomers by dissociative ionization and neutralization of linear, branched, and cyclic precursors were unsuccessful. Spectra of C[sub 4][sup +] from [sup 13]CH[sub 2]=CHCH=[sup 13]CH[sub 2] and C[sub 3][sup +] from CH[sub 2]=[sup 13]CH=CH[sub 3] showed complete [sup 13]C/[sup 12]C scrambling. Product abundances from the dissociation of C[sub n], C[sub n][sup [minus]](n = 2-6) and C[sub n][sup +](n = 2-7) make possible the designation of more accurate heat-of-formation values of experimental and theoretical values reported previously.

• Research Organization: Cornell Univ., Ithaca, NY (United States)
• OSTI ID: 5651061
• Resource Relation: Other Information: Thesis (Ph.D)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BUTENES
DISSOCIATION HEAT
MASS SPECTROSCOPY
HEXENES
CHARGE EXCHANGE
ETHANOL
EXPERIMENTAL DATA
IONIZATION
ISOMERIZATION
RESOLUTION
ALCOHOLS
ALKENES
CHEMICAL REACTIONS
DATA
ENTHALPY
HYDROCARBONS
HYDROXY COMPOUNDS
INFORMATION
NUMERICAL DATA
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
REACTION HEAT
SPECTROSCOPY
THERMODYNAMIC PROPERTIES
400102* - Chemical & Spectral Procedures
400201 - Chemical & Physicochemical Properties