Photoionization mass spectrometric studies of SiH/sub n/ (n = 1--4)
A photoionization mass spectrometric study of SiH/sub 4/ at T = 150 K reveals the presence of SiH/sup +//sub 4/ with an adiabatic threshold at 11.00 +- 0.02 eV. The implications for the structure of this Jahn--Teller split state are discussed. The appearance potentials of SiH/sup +//sub 2/ and SiH/sup +//sub 3/ are 11.54 +- 0.01 eV and less than or equal to12.086 eV, respectively. The reaction of F atoms with SiH/sub 4/ generates SiH/sub 3/ (X /sup 2/A/sub 1/), SiH/sub 2/ (X /sup 1/A/sub 1/ and a /sup 3/B/sub 1/), and SiH (X /sup 2/Pi) in sufficient abundance for photoionization studies. The measured adiabatic ionization potentials (eV) are: SiH/sub 3/, 8.01 +- 0.02; SiH/sub 2/ (X /sup 1/A/sub 1/), 9.15 +- 0.02 or 9.02 +- 0.02; SiH/sub 2/ (a /sup 3/B/sub 1/), 8.24/sub 4/ +- 0.02/sub 5/; SiH, 7.91 +- 0.01. The singlet--triplet splitting in SiH/sub 2/ is either 0.78 +- 0.03 or 0.91 +- 0.03 eV. The dissociation energy of SiH is 2.98 +- 0.03 eV. A Rydberg series is observed, converging to SiH/sup +/ (a /sup 3/Pi) at 10.21 +- 0.01 eV. Heats of formation of the various neutral and ionic species are presented, as are the stepwise bond energies of SiH/sub 4/.
- Research Organization:
- Physics Division, Argonne National Laboratory, Argonne, Illinois
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 6772582
- Journal Information:
- J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 86:3; ISSN JCPSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
640302 -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
DISSOCIATION ENERGY
ENERGY
ENERGY LEVELS
ENTHALPY
EXCITED STATES
FORMATION HEAT
HYDRIDES
HYDROGEN COMPOUNDS
IONIZATION
IONIZATION POTENTIAL
MASS SPECTROSCOPY
ORGANIC COMPOUNDS
ORGANIC SILICON COMPOUNDS
PHOTOIONIZATION
PHYSICAL PROPERTIES
REACTION HEAT
RYDBERG STATES
SILANES
SILICON COMPOUNDS
SPECTROSCOPY
THERMODYNAMIC PROPERTIES