Field ionization of high-Rydberg fragments produced after inner-shell photoexcitation and photoionization of the methane molecule

Journal Article · Mon Sep 21 04:00:00 EDT 2015 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4931105· OSTI ID:22489604

Sankari, A. ^[1]; Kettunen, J. A. ^[2]; Stråhlman, C. ^[3]; Álvarez Ruiz, J. ^[4]; Richter, R. ^[5]

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1. Department of Physics, Lund University, P.O. Box 118, 22100 Lund (Sweden)
2. Department of Physics, University of Oulu, P.O. Box 3000, 90014 Oulu (Finland)
3. MAX IV Laboratory, Lund University, P.O. Box 118, 22100 Lund (Sweden)
4. Colegio Los Naranjos, Fuenlabrada, 28941 Madrid (Spain)
5. Elettra-Sincrotrone Trieste, Area Science Park Basovizza, 34149 Trieste (Italy)

We have studied the production of neutral high-Rydberg (HR) fragments from the CH{sub 4} molecule at the C 1s → 3p excitation and at the C 1s ionization threshold. Neutral fragments in HR states were ionized using a pulsed electric field and the resulting ions were mass-analyzed using an ion time-of-flight spectrometer. The atomic fragments C(HR) and H(HR) dominated the spectra, but molecular fragments CH{sub x}(HR), x = 1-3, and H{sub 2}(HR) were also observed. The production of HR fragments is attributed to dissociation of CH{sub 4}{sup +} and CH{sub 4}{sup 2+} ions in HR states. Just above the C 1s ionization threshold, such molecular ionic states are created when the C 1s photoelectron is recaptured after single or double Auger decay. Similar HR states may be reached directly following resonant Auger decay at the C 1s → 3p resonance. The energies and geometries of the parent and fragment ions have been calculated in order to gain insight into relevant dissociation pathways.

• OSTI ID: 22489604
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 11 Vol. 143; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
DISSOCIATION
ELECTRIC FIELDS
EXCITATION
IONS
METHANE
MOLECULES
PHOTOIONIZATION
PULSES
RESONANCE
SPECTRA
TIME-OF-FLIGHT SPECTROMETERS