DISPERSED FLUORESCENCE STUDIES OF QUARTET STATE ALKALI TRIMERS
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Date
1996
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
The high spin states of $Na_{3}$ and $K_{3}$ can be formed on the surface of large helium clusters by the aggregation of three alkali atoms with parallel electron spins. The emission spectrum of the $2^{4}E^{\prime} - 1^{4}A_{2}^{\prime}$ transition of $Na_{3}$ reveals that a non-adiabatic spin flip process occurs in the excited state that leads to an intersystem corssing into the doublet manifold of the trimer. A total of three channels of fluorescence are observed in both $Na_{3}$ and $K_{3}$: a) direct emission to the lowest quartet state of the trimer, b) $n^{2}P_{3/2, 1/2} - n^{2}S_{1/2}$ atomic fluorescence, and c) fluorescence from the singlet dimer (B) $1^{1}\Pi_{u}-(X)1^{1}\Sigma^{+}_{g}$ transition. The latter two correspond to the emission of the dissociation products of the doublet trimer after curve crossing. Vibrational analysis of the lowest quartet state of $Na_{3}$ provides spectroscopic data with which to test ab-initio potential surfaces. The study of the quartet state trimars provides information on the three-body component of the intermolecular energy in these van der Waals molecules. The possibility for time resolved dynamical studies of this simple unimolecular reaction will also be discussed.
Description
Author Institution: Department of Chemistry, Princeton University; Fakult\'{a}t f\""{u}r Physik, Universit\""{a}t Bielefeld, Universit\""{a}tsstr; Department of Chemistry, University of Gd\'{a}nsk