Fit of a sum of exponential functions to experimental data points. (English) Zbl 0854.65009

Monjoie, F. S.; Garnir, H. P.

Comput. Phys. Commun. 74, No. 1, 1-8 (1993).

Summary: Expfit is a program aimed at the analysis of light decay curves in beam-foil spectroscopy experiments. It fits, using the least squares method, a sum of exponential functions to experimental data points. A new technique, based on statistical tests, has been implemented to find the best number of parameters so that in most cases the fit is fully automatized. However, the user may give the initial parameters and determine the number of parameters to be adjusted or let Expfit find the best number of needed parameters. Expfit can print a report presenting the results of the fit under tabular and graphical format. Thanks to its graphic interface, built following the Apple Macintosh human interface guidelines, the program is easy to use.

MSC:

65D10	Numerical smoothing, curve fitting
78A45	Diffraction, scattering

Keywords:

curve fitting; Expfit; program; light decay curves; spectroscopy; least squares method; sum of exponential functions; experimental data; statistical tests

Software:

Expfit

References:

[1]	Baskin, S., Beam-Foil Spectroscopy, (Topics in Current Physics (1976), Springer: Springer Berlin)
[2]	Irwin, D. J.G.; Livingston, A. E., A program for the extraction of radiative lifetimes from experimental beam-foil intensity decay data, Comput. Phys. Commun., 7, 95 (1974)
[3]	Provencher, S. W., An eigenfunction expansion method for the analysis of exponential decay curves, J. Chem. Phys., 64, 2772 (1976)
[4]	Provencher, S. W., A Fourier method for the analysis of exponential decay curves, Biophys. J., 16, 27 (1976)
[5]	Engström, L., CANDY, a computer program to perform an ADNC analysis of cascade correlated decay curves, Nucl. Instrum. Methods, 202, 369 (1982)
[6]	Apple, Computer, Human Interface Guidelines, The Apple Desktop Interface (1987), Addison-Wesley: Addison-Wesley Reading, MA
[7]	Lightspeed Pascal V4 (1992), Symantec corporation
[8]	Bevington, P., Data Reduction and error analysis for the physical sciences, ((1969), McGraw-Hill: McGraw-Hill New York), 189-200
[9]	Marquardt, D. W., An algorithm for least-squares estimation of nonlinear parameters, J. Soc. Ind. Math., 11, 431 (1963) · Zbl 0112.10505
[10]	(Abramowitz, M.; Stegun, A., Handbook of mathematical functions (1964), National Bureau of Standards: National Bureau of Standards Washington, DC), 947-948 · Zbl 0171.38503
[11]	Monjoie, F. S.; Garnir, H. P.; Baudinet-Robinet, Y.; Dumont, P. D., Empirical relation for electronic stopping power of heavy ions in carbon, J. Phys. Paris, 41, 599 (1980)
[12]	Monjoie, F. S.; Garnir, H. P., Empirical relation for nuclear stopping power, J. Phys. Paris, 41, 31 (1980)
[13]	Apple, Computer, (Inside Macintosh, Vols. 1-6 (1985-1991), Addison-Wesley: Addison-Wesley Reading, MA)
[14]	Baudinet-Robinet, Y.; Dumont, P. D.; Garnir, H. P., Measurement of the 2p3s \(^1P\)° lifetime in OIII with the beam-foil-laser method, Phys. Rev. A, 43, 4022 (1991), and references therein