Date of Award

12-1993

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Department of Engineering Physics

First Advisor

Glen P. Perram, PhD

Abstract

Vibrational transfer and electronic quenching in the lower vibrational levels (v' < 3) of the B3π(0u+) state of 79Br2 were investigated using spectrally resolved, temporally resolved laser induced fluorescence techniques. Spectrally resolved emissions from collisionally populated Br2(B) vibrational levels were observed for Br2 and rare gas collision partners. Vibrational transfer was efficient in the non-predissociative vibrational levels and was adequately described by the Montroll-Shuler model for harmonic oscillators. A single fundamental rate coefficient for vibrational transfer from v' = 1 to v' = 0, kv(1,0), characterizes vibrational relaxation. For Br2, the value was k,(1,0) = 3.6 ± 0.4 x 10-11 cm3/molec-sec. For rare gas collisions, values ranged from kv(1,0) = 2.5 ± 0.3 x 10-11 cm3/molec-sec for helium to kv(1,0) = 3.1 ± 0.4 x 10-1 cm3/molec-sec for xenon. Electronic quenching rates for the observed vibrational levels were obtained from the same data. For Br2, the quenching rate coefficient was kq = 3.7 ± 1.2 x 1011 cm 3/molec-sec. Quenching rate coefficients for the rare gases were smaller, kq = 8.0 ± 1.2 x 1012 cm 3/molec-sec. Additionally, the spectroscopy of high vibrational levels in the 79Br81Br X1 Σg+ ground electronic state was investigated using spectrally resolved, pulsed laser induced fluorescence Vrom low J levels in the B3Π(0u+) state. Over 100 bandheads were identified for transitions from 15 ≤ v' ≤ 21 to 1 ≤ v" ≤ 27. The calculated spectroscopic constants, ωe" = 323.1 ± 1.5 cm-1, ωe" = 1.02 ± 0.1 cm-1 and ωeYe" = -3.77 ± 0.2 x 10-3 cm-1, are valid for v" ≤ 27.

AFIT Designator

AFIT-DS-ENP-93-04

DTIC Accession Number

ADA273795

Comments

The author's Vita page is omitted.

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