About the software for fitting EIS. Part 6

Part 1

Part 2

Part 3

Part 4

Part 5

The next program useful for the fitting of complex equivalent circuits is based on the program LEVM developed by Prof. Ross Macdonald, to whom all possible credits should be addressed. The program itself can be downloaded for free from the site www.jrossmacdonald.com. It is very powerful, although not too user friendly. A comprehensive manual can be downloaded from the same site. The bad news is that even such a helpful manual is no substitute for the long work of mastering the program. The good news is that many other programs make use of LEVM and present it to an end user in much easier and intuitive form. One of such programs is MEISP developed by Dr. Evgenij Barsukov for KOREA KUMHO PETROCHEMICAL CO., LTD. The copyright holder (KUMHO PETROCHEMICAL) discontinued the distribution of the commercial version of MEISP some years ago and, as Dr. Barsukov writes, "it looks to me that since commercial version no longer exists, it is a fair game to use the trial version as long as you want. It appears also that due to some changes in Windows OS, the expiration mechanism no longer works." A trial version of MEISP can be dowloaded on the website of Dr. Barsukov. This version works just fine at least with Windows 7, Windows Vista and Windows XP.

A couple of words about MEISP:

(+) De facto, it is free.

(+) It contains a very rich library of typical impedance spectra and equivalent circuits with references to original papers and books.

(+) It is equipped with an editor of custom equivalent circuits.

(+) The fits made by MEISP are very good.

(+) Fit parameters are available.

(-) The editor of equivalent circuits is a bit less user friendly than in other programs.

(-) You cannot export plots, neither can you export datatable to build the fitted plot in another program. Still, if you know the parameters of an equivalent ciruit, you can use them in another program.

And now the results of the fits made in MEISP for our impedance spectrum. (Screenshots, of course):

MEISP

 Since no statistical information is available, it is not possible to compare the equivalent circuits. In other words, MEISP is a great tool for the determination of parameters of an equivalent circuit. However, it cannot be used by itself. Rather you have to use another program for nice plots and statistics.