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Proceedings Paper

Semiempirical quantum-mechanical calculations of DMABN spectral properties
Author(s): M. Brozis; V. I. Tomin
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Paper Abstract

DMABN, 4-(dimethylaminbenzylonitrile), is the archetype molecule with two broad bands in the luminescence spectra [1,2]. Until now the majority of researchers have connected dual luminescence with different mechanisms of electronic density change (charge transfer) in the excited state. However, the exact nature of its mechanism is still under discussion. Such a model would be the crucial point for the right calculation of photoreactions with CT participation and, therefore, the determination ofthe charge transfer mechanism is the problem ofgreat practical importance. For the proper choice of the model and its groundation a more detailed study is required for establishing additional features ofthe process creating charge transfer in the excited state. We present the results ofquantum-mechanical calculations for DMABN and focus on: 1 . calculations of fundamental characteristics in the states with different geometry and energy; 2. possibilities to create spectral broadening and a study ofthe features ofsuch broadening; The computer programs the HyperChem v.5.0 and the MOPAC 2000 are used in the calculations. A geometry optimization of the ground state is carried out using the PM5 method. Free molecule energy and the values of dipole moments in the excited and the ground states are calculated with the ZINDO/S Cl method assuming that the benzene ring has a fixed flat structure. We have studied geometries with two spatial angles (Fig. ): (p- the torsion (or twist) angle between the planes of the dimethyl group and the benzene ring (0- the angle between the NCC plane and the N-benzene3 bond (wagging angle), the change of which leads to a pyramidal structure

Paper Details

Date Published: 1 June 2005
PDF: 4 pages
Proc. SPIE 5849, Fifth Workshop on Atomic and Molecular Physics, (1 June 2005); doi: 10.1117/12.629487
Show Author Affiliations
M. Brozis, Pomeranian Pedagogical Academy in Slupsk (Poland)
V. I. Tomin, Pomeranian Pedagogical Academy in Slupsk (Poland)

Published in SPIE Proceedings Vol. 5849:
Fifth Workshop on Atomic and Molecular Physics
Jerzy Kwela; Ryszard Drozdowski; Tomasz J. Wasowicz, Editor(s)

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