The Genuine Article Number: RW881
Cha C., Weinkauf R., Boesl U .
LASER SPECTROSCOPY OF MOLECULAR IONS - THE (A)OVER-
TILDE-(X)OVER-TILDE TRANSITION OF THE ACETYLENE RADICAL CATION
Journal of Chemical Physics. 103(13):5224-5235, 1995 Oct 1.
Multiphoton dissociation spectra. Photoelectron-spectroscopy. Vinylidene.
States. Isomerization. C2h2+. Rearrangement. Ionization. Excitation.
Resonance-enhanced multiphoton-dissociation spectroscopy has been used
to measure the first highly resolved UV spectrum of the acetylene radical
cation. The bent structure of the ionic (A) over tilde state could be proved. In
the (A) over tilde-(X) over tilde-spectrum progressions of all three bending
modes of bent acetylene. Their frequencies, anharmonicities and estimated
potential thresholds are given. Furthermore, for the origin and the 5a(0)(2)
band (out-of-plane cis-bending mode) rotationally resolved spectra have
been obtained and rotational constants A, B, and D-K have been determined
as well as a directly measured value of the (X) over tilde-state spin-orbit
splitting. From rotational linewidths or envelopes information about single
vibrational lifetimes has been deduced; a mode-specific behavior of these
lifetimes has been found. Several nonradiative processes involving
isomerization to vinylidene seem to be important in the energy region of our
spectrum. (C) 1995 American Institute of Physics. [References: 50]
Physical chemistry/chemical physics.
Current Contents/Physical, Chemical & Earth Sciences
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