An assessment of the Padé-Laplace method for transient electric birefringence decay analysis

Abstract

We implemented and tested the Padé-Laplace method for analyzing a sum of exponential decays, and applied it to transient electric birefringence decay measurements on DNA samples. The Padé-Laplace method involves integrating the decay data to calculate the Taylor expansion of the Laplace transform. The Padé approximant of the Laplace transform can be calculated from the Taylor series, and is then used to determine the number and value of the time constants in the decay. False solutions with complex and positive (diverging) exponentials were obtained from data but these false solutions were easily discarded. We found the method to be remarkably robust to random noise, but very sensitive to baseline errors. The same data sets were analyzed using the well-established deconvolution program CONTIN. The Padé-Laplace method could resolve time constants better than CONTIN from noisy data, but CONTIN compensated for baseline errors much more effectively. The time for executing either analysis on a microcomputer was almost the same.