Vibrations of pyrazine and its ion as studied by threshold ionization spectroscopy

Journal Article · Sun Aug 15 04:00:00 EDT 1993 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.465247· OSTI ID:6325488

Zhu, L; Johnson, P ^[1]

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1. Department of Chemistry, State University of New York, Stony Brook, New York 11794 (United States)

The pump--probe threshold ionization photoelectron spectra of pyrazine have been recorded using nine different vibrations of [ital S][sub 1] as intermediate resonances. The extensive vibrational structure in these spectra of the ionic ground state have enabled the measurement of 12 of its vibrational frequencies and their assignments. Three new vibrational assignments of [ital S][sub 1] are also made. MP2/6-31G* calculations of the vibrational frequencies of the neutral ground, [ital S][sub 1], and the ionic ground state are compared with the experimental values, finding that certain vibrations of [ital S][sub 1] and the ion which engage in extensive vibronic coupling are not properly determined by the calculated force field. Most vibrational frequencies are accurately reproduced, however. Variations in the complexity of the threshold ionization spectra with the level of [ital S][sub 1] excitation indicate that internal vibrational relaxation is taking place at a very low energy in that state, possibly involving vibronic interactions and mixing with the triplet manifold.

• DOE Contract Number: FG02-86ER13590
• OSTI ID: 6325488
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 99:4; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

664400* -- Experimentally Derived Information on Atomic & Molecular Properties-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION
AZINES
CHARGED PARTICLES
COUPLING
ELECTRON SPECTROSCOPY
ENERGY
ENERGY LEVELS
EXCITED STATES
GROUND STATES
HETEROCYCLIC COMPOUNDS
IONS
MOLECULAR IONS
MULTIPLETS
OPTICAL PUMPING
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
PUMPING
PYRAZINES
RESONANCE ABSORPTION
SORPTION
SPECTROSCOPY
THRESHOLD ENERGY
TRIPLETS
VIBRATIONAL STATES