Phosphorescence excitation spectroscopy in supersonic jets. The lowest triplet state of pyrazine

Journal Article · Mon Feb 01 04:00:00 EST 1988 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.454132· OSTI ID:5647226

Tomer, J L; Holtzclaw, K W; Pratt, D W; Spangler, L H

Motivated principally by dynamic issues, we have observed and assigned the laser-induced phosphorescence excitation spectrum of pyrazine in the collision-free environment of a supersonic jet. The origin of the lowest triplet state (T/sub 1/) lies at 26 820 cm/sup -1/ and exhibits a symmetric parallel-type rotational contour, confirming that this state is /sup 3/B/sub 3//sub u/ (n..pi..*) with an equilibrium geometry that is similar to those of the S/sub 0/ (/sup 1/A/sub g/) and S/sub 1/ (/sup 1/B/sub 3//sub u/ , n..pi..*) states. Thirty vibrational bands were also observed in the approx.4000 cm/sup -1/ interval between the T/sub 1/ and S/sub 1/ origins. Of these, the 13 lower energy bands all exhibit parallel-type contours and may be assigned as T/sub 1/reverse arrowS/sub 0/ transitions, principally involving totally symmetric modes. The 17 higher energy bands exhibit both parallel and perpendicular contours and may be assigned as S/sub 1/reverse arrowS/sub 0/ hot band transitions, some involving nontotally symmetric modes. No evidence for a second, ..pi pi..* triplet state lying below the S/sub 1/ origin is found, nor is there any evidence for rapid relaxation of any of the zero-order T/sub 1/ levels at a resolution of approx.1 cm/sup -1/.

• Research Organization: Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
• OSTI ID: 5647226
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 88:3; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION SPECTRA
AZINES
BEAMS
ELECTRONIC STRUCTURE
FLUID FLOW
HETEROCYCLIC COMPOUNDS
JETS
LUMINESCENCE
MOLECULAR BEAMS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOSPHORESCENCE
PYRAZINES
SPECTRA
SUPERSONIC FLOW
ULTRAVIOLET SPECTRA