MSM 99
MSM 99
Technical Proceedings of the 1999 International Conference on Modeling and Simulation of Microsystems

Computational Materials Chapter 3

New Materials Design.Free-Base Porphyrin and Its Meso-Tetrahalogenated Derivatives

Authors: K.A. Nguyen and R. Pachter

Affilation: Air Force Research Laboratory, United States

Pages: 57 - 60

Keywords: modeling and simulation of optical limiting materials, ab initio electronic structure, porphyrin derivatives, electronic spectra, molecular structures

Abstract:
Ab initio electronic structure theory has been applied to predict the structures and electronic spectra of free-base porphyrin (PH2) and its meso-tetrahalogenated derivatives (m-PX8H2, X = F, Cl, Br). Structures, singlet-triplet energy gaps, and electronic spectra are predicted using the B3LYP method in conjunction with the 6-31G(d) basis set and the effective core potentials/basis sets of Stevens et al. Minimum energy structures of the lowest triplet excited states (T1) were found to retain D2h symmetry with stretched Cb-Cb and Cb-Cm bond distances. We found that halogenation at the four meso-positions significantly changes the ground state excitation energies and the singlet-triplet gap for the free-base parent compound.

New Materials Design.Free-Base Porphyrin and Its Meso-Tetrahalogenated Derivatives

ISBN: 0-9666135-4-6
Pages: 697