The pulsed field ionization spectrum and lifetimes of the states at the S sub 1 origin of pyrazine

Journal Article · Thu Aug 15 04:00:00 EDT 1991 · Journal of Chemical Physics; (USA)

DOI:https://doi.org/10.1063/1.460979· OSTI ID:5656380

Hillenbrand, S; Zhu, L; Johnson, P ^[1]

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

The pump--probe pulsed field ionization (PFI) spectrum through the origin of {ital S}{sub 1} of pyrazine reveals three distinct types of peaks. At low excess energy above the lowest ionization potential (I.P.) are sharp peaks with Franck--Condon factors representative of the singlet intermediate state. At ionization wavelengths {lt}208 nm, the Franck--Condon overlap allows for the observation of primarily the triplet component of the pumped superposition state. At this energy, some resolved structure has a measured lifetime {gt}10 {mu}s and is determined to be the result of ionization of relaxed triplet states populated through vibrational dissociation of van der Waals clusters. A diffuse structure in the same region is the result of ionization of monomer intermediate states with lifetimes that vary with the ionizing wavelength. From this variation, it can be surmised that there is an inhomogeneous sample of intermediate states, possibly due to a mixture of unrelaxed molecular eigenstates and decoupled triplets populated by an intramolecular vibrational relaxation within the triplet manifold.

• DOE Contract Number: FG02-86ER13590
• OSTI ID: 5656380
• Journal Information: Journal of Chemical Physics; (USA), Journal Name: Journal of Chemical Physics; (USA) Vol. 95:4; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
AZINES
ENERGY LEVELS
EXCITED STATES
FRANCK-CONDON PRINCIPLE
HETEROCYCLIC COMPOUNDS
IONIZATION POTENTIAL
LIFETIME
MULTIPLETS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRAZINES
ROTATIONAL STATES
TRIPLETS