ISSN:
1089-7690
Quelle:
AIP Digital Archive
Thema:
Physik
,
Chemie und Pharmazie
Notizen:
Threshold photoelectron spectra of 12CO2 and 13CO2 have been obtained from the onset at 900 A(ring) (13.75 eV) to 620 A(ring) (20 eV) at a 9 meV resolution using dispersed synchrotron radiation with a 0.3 A(ring) bandpass. A number of forbidden and/or previously unobserved transitions have been assigned for the X˜, A˜, B˜, and C˜ states of CO+2. Photoelectron spectra by electron time of flight at selected excitation wavelengths in the Franck–Condon gap region below the A˜ state, reveal the autoionization of neutral valence states as well as Rydberg series converging to the A˜ 2Πu and B˜ 2Σ+u states. The photoelectron energy distribution obtained upon excitation of the Rydberg states is consistent with that given by the Bardsley–Smith model for autoionization, while the superexcited valence states decay via a resonance autoionization process proposed previously by Guyon, Baer, and Nenner. These valence states are also responsible for the strong enhancement of vibrationally forbidden transitions, such as (000)→(010). Finally, several threshold electron peaks in the region between the A˜ and C˜ states, whose origin can be attributed to autoionization, are shown to be highly sensitive to isotopic substitution.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.451736
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