Date of Award

3-13-2001

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Department of Engineering Physics

First Advisor

Glen P. Perram, PhD

Abstract

More than 100,000 spectral features from a Bi2(X1 Σ+g → A(0+u)) absorption spectrum, encompassing 0 ≤ v' ≤ 91, 0 ≤ v" ≤ 7 and J2(A). Ground state constants, reported by Barrow et al. [1], remain unchanged. The new constants are used to redefine the A-state potential using traditional RKR methods and to set the dissociation energy at De = 29,913 cm"1, which correlates A-state dissociation products to 4S + 2D atoms. A pulsed dye laser apparatus was used to obtain lifetime data for Bi2A(0+u) → X1 Σ+g) transitions. The collision-free lifetimes for v'=20 to v-39, and J ≤ 105, were investigated for effects of heterogeneous predissociation. The observed predissociation rates, Γ = kpd,v’J (J+1), establish the range kpd,v’ = 153 sec-1 to 1.5x105 sec-1 for v'=21 to v'=39. Rapid predissociation and the dense Bi2(A→X) spectrum required both traditional lifetime measurements and synthetic spectrum fits to determine the full range of observed rates. Extensive numerical analysis fails to produce an appropriate analytic repulsive potential responsible for the observed A-state predissociation implying that current numerical tools, theoretical constructs, and knowledge of the low-lying electronic states in Bi2 are inadequate to describe the predissociation found in this study.

AFIT Designator

AFIT-DS-ENP-01-01

DTIC Accession Number

ADA390968

Comments

The author's Vita page is omitted.

Plain-text title: Spectroscopic Constants, Lifetimes and Predissociation Rates for Bi2A(0+u)

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