Triplet State Photophysics

Extinction coefficients of triplet-triplet absorption spectra of organic molecules in condensed phases:
A least-squares analysis

A global least-squares technique designed to handle large data sets, comprising mainly of relative measurements, is developed and a linearization procedure is used to reduce the inherently nonlinear problem to a traditional multivariate linear regression. The technique developed here is used to evaluate extinction coefficients of triplet-triplet absorption (TTA) spectra of organic molecules in condensed phases.

A previous assumption, that there are no solvent effects on the TTA spectra, is investigated and modified so that a group of compounds measured in benzene is treated separately. The set of 445 extinction coefficient values obtained from the global least-squares fit is used in a hierarchy of TTA extinction coefficient standards. Further solvent effects such as the separation of polar and nonpolar media and the influence of temperature are probed.

Published by:

I. Carmichael, W.P. Helman, and G.L. Hug
J. Phys. Chem. Ref. Data 16 239-60 (1987). __ Ordering info.

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This document prepared by Ian Carmichael

e-mail: madden.1@nd.edu

Work supported by:

Office of Basic Energy Sciences
United States Department of Energy

Standard Reference Data
National Institute of Standards and Technology
Last update: Mar. 15, 2005