ISSN:
1089-7690
Quelle:
AIP Digital Archive
Thema:
Physik
,
Chemie und Pharmazie
Notizen:
We investigated highly predissociative transitions D 2Π–B 2Σ−(0-0) of CH in an oxyacetylene flame with two-color resonant four-wave mixing, in which two grating beams are in resonance with the D–B transition and the pump (and signal) beam is resonant with a selected B–X transition. A total of 86 predissociative lines in six branches are observed, corresponding to excitation of the D state up to N′=16; in previous experiments lines up to only N′=6 were observed. Observed rovibronic transitions of the D–B(0-0) band are fitted to known Hamiltonians to yield improved spectral parameters of the D 2Π (v=0) state. The parameters for centrifugal distortion (D,H) and Λ doubling (p,q,qD) of the D 2Π (v=0) state are deduced for the first time. The predissociative line width is about 2 cm−1 for the rotational level with N′=1 and it gradually increases with N′; for N′=15 the width is about 7 cm−1. Predissociation mechanisms of the D 2Π state are discussed. A barrier height ∼5600 cm−1 for the D state is estimated based on observed predissociative lifetimes. © 1999 American Institute of Physics.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.479753
